diff --git a/apps/server/src/domains/game/GameManager.ts b/apps/server/src/domains/game/GameManager.ts
index 799d858..118abb7 100644
--- a/apps/server/src/domains/game/GameManager.ts
+++ b/apps/server/src/domains/game/GameManager.ts
@@ -1,28 +1,36 @@
 import { type TickData } from "./loop/GameLoop";
 import { Player } from "./entities/player/Player.js";
-import { GameSessionService } from "./application/services/GameSessionService";
+import { GameRoomSession } from "./application/services/GameRoomSession";
+import { GameSessionLifecycleService } from "./application/services/GameSessionLifecycleService";
+import { GamePlayerOperationService } from "./application/services/GamePlayerOperationService";
 
 // プレイヤー集合の生成・更新・参照管理クラス
 export class GameManager {
-  private gameSessionService: GameSessionService;
+  private sessions: Map<string, GameRoomSession>;
+  private playerToRoom: Map<string, string>;
+  private lifecycleService: GameSessionLifecycleService;
+  private playerOperationService: GamePlayerOperationService;
 
   constructor() {
-    this.gameSessionService = new GameSessionService();
+    this.sessions = new Map();
+    this.playerToRoom = new Map();
+    this.lifecycleService = new GameSessionLifecycleService(this.sessions, this.playerToRoom);
+    this.playerOperationService = new GamePlayerOperationService(this.sessions, this.playerToRoom);
   }
 
   // 外部（GameHandlerなど）から開始時刻を取得できるようにする
   getRoomStartTime(roomId: string): number | undefined {
-    return this.gameSessionService.getRoomStartTime(roomId);
+    return this.lifecycleService.getRoomStartTime(roomId);
   }
 
   // プレイヤー登録解除処理
   removePlayer(id: string) {
-    this.gameSessionService.removePlayer(id);
+    this.playerOperationService.removePlayer(id);
   }
 
   // 指定プレイヤー座標更新処理
   movePlayer(id: string, x: number, y: number) {
-    this.gameSessionService.movePlayer(id, x, y);
+    this.playerOperationService.movePlayer(id, x, y);
   }
 
   /**
@@ -37,11 +45,11 @@
     onTick: (data: TickData) => void,
     onGameEnd: () => void
   ) {
-    this.gameSessionService.startRoomSession(roomId, playerIds, onTick, onGameEnd);
+    this.lifecycleService.startRoomSession(roomId, playerIds, onTick, onGameEnd);
   }
 
   // 指定ルームのプレイヤーを取得
   getRoomPlayers(roomId: string): Player[] {
-    return this.gameSessionService.getRoomPlayers(roomId);
+    return this.lifecycleService.getRoomPlayers(roomId);
   }
 }
\ No newline at end of file
diff --git a/apps/server/src/domains/game/application/services/GamePlayerOperationService.ts b/apps/server/src/domains/game/application/services/GamePlayerOperationService.ts
new file mode 100644
index 0000000..9c039c7
--- /dev/null
+++ b/apps/server/src/domains/game/application/services/GamePlayerOperationService.ts
@@ -0,0 +1,58 @@
+import { logEvent } from "@server/logging/logEvent";
+import { GameRoomSession } from "./GameRoomSession";
+
+type SessionStore = Map<string, GameRoomSession>;
+type PlayerRoomIndex = Map<string, string>;
+
+export class GamePlayerOperationService {
+  constructor(
+    private sessions: SessionStore,
+    private playerToRoom: PlayerRoomIndex
+  ) {}
+
+  public movePlayer(id: string, x: number, y: number): void {
+    const roomId = this.playerToRoom.get(id);
+    if (!roomId) {
+      logEvent("GameSessionService", {
+        event: "MOVE",
+        result: "ignored_player_not_in_session",
+        socketId: id,
+      });
+      return;
+    }
+
+    this.sessions.get(roomId)?.movePlayer(id, x, y);
+  }
+
+  public removePlayer(id: string): void {
+    const roomId = this.playerToRoom.get(id);
+    if (!roomId) {
+      logEvent("GameSessionService", {
+        event: "REMOVE_PLAYER",
+        result: "ignored_player_not_in_session",
+        socketId: id,
+      });
+      return;
+    }
+
+    const session = this.sessions.get(roomId);
+    if (!session) {
+      this.playerToRoom.delete(id);
+      return;
+    }
+
+    const removed = session.removePlayer(id);
+    this.playerToRoom.delete(id);
+
+    if (removed && session.isEmpty()) {
+      session.dispose();
+      this.sessions.delete(roomId);
+      logEvent("GameSessionService", {
+        event: "REMOVE_PLAYER",
+        result: "session_disposed_empty_room",
+        roomId,
+        socketId: id,
+      });
+    }
+  }
+}
\ No newline at end of file
diff --git a/apps/server/src/domains/game/application/services/GameSessionLifecycleService.ts b/apps/server/src/domains/game/application/services/GameSessionLifecycleService.ts
new file mode 100644
index 0000000..333d259
--- /dev/null
+++ b/apps/server/src/domains/game/application/services/GameSessionLifecycleService.ts
@@ -0,0 +1,67 @@
+import { config } from "@repo/shared";
+import { type TickData } from "../../loop/GameLoop";
+import { logEvent } from "@server/logging/logEvent";
+import { GameRoomSession } from "./GameRoomSession";
+
+type SessionStore = Map<string, GameRoomSession>;
+type PlayerRoomIndex = Map<string, string>;
+
+export class GameSessionLifecycleService {
+  constructor(
+    private sessions: SessionStore,
+    private playerToRoom: PlayerRoomIndex
+  ) {}
+
+  public getRoomStartTime(roomId: string): number | undefined {
+    return this.sessions.get(roomId)?.getStartTime();
+  }
+
+  public getRoomPlayers(roomId: string) {
+    return this.sessions.get(roomId)?.getPlayers() ?? [];
+  }
+
+  public startRoomSession(
+    roomId: string,
+    playerIds: string[],
+    onTick: (data: TickData) => void,
+    onGameEnd: () => void
+  ) {
+    if (this.sessions.has(roomId)) {
+      logEvent("GameSessionService", {
+        event: "START_GAME_LOOP",
+        result: "ignored_already_running",
+        roomId,
+      });
+      return;
+    }
+
+    const tickRate = config.GAME_CONFIG.PLAYER_POSITION_UPDATE_MS;
+    const session = new GameRoomSession(roomId, playerIds);
+
+    playerIds.forEach((playerId) => {
+      this.playerToRoom.set(playerId, roomId);
+    });
+
+    this.sessions.set(roomId, session);
+    session.start(tickRate, onTick, () => {
+      this.clearRoomPlayerIndex(roomId);
+      this.sessions.delete(roomId);
+      onGameEnd();
+    });
+
+    logEvent("GameSessionService", {
+      event: "START_GAME_LOOP",
+      result: "started",
+      roomId,
+      playerCount: playerIds.length,
+    });
+  }
+
+  private clearRoomPlayerIndex(roomId: string): void {
+    Array.from(this.playerToRoom.entries()).forEach(([playerId, mappedRoomId]) => {
+      if (mappedRoomId === roomId) {
+        this.playerToRoom.delete(playerId);
+      }
+    });
+  }
+}
\ No newline at end of file
diff --git a/apps/server/src/domains/game/application/services/GameSessionService.ts b/apps/server/src/domains/game/application/services/GameSessionService.ts
deleted file mode 100644
index 020282b..0000000
--- a/apps/server/src/domains/game/application/services/GameSessionService.ts
+++ /dev/null
@@ -1,113 +0,0 @@
-import { config } from "@repo/shared";
-import { type TickData } from "../../loop/GameLoop";
-import { logEvent } from "@server/logging/logEvent";
-import { GameRoomSession } from "./GameRoomSession";
-
-export class GameSessionService {
-  private sessions: Map<string, GameRoomSession>;
-  private playerToRoom: Map<string, string>;
-
-  constructor() {
-    this.sessions = new Map();
-    this.playerToRoom = new Map();
-  }
-
-  public getRoomStartTime(roomId: string): number | undefined {
-    return this.sessions.get(roomId)?.getStartTime();
-  }
-
-  public getRoomPlayers(roomId: string) {
-    return this.sessions.get(roomId)?.getPlayers() ?? [];
-  }
-
-  public startRoomSession(
-    roomId: string,
-    playerIds: string[],
-    onTick: (data: TickData) => void,
-    onGameEnd: () => void
-  ) {
-    if (this.sessions.has(roomId)) {
-      logEvent("GameSessionService", {
-        event: "START_GAME_LOOP",
-        result: "ignored_already_running",
-        roomId,
-      });
-      return;
-    }
-
-    const tickRate = config.GAME_CONFIG.PLAYER_POSITION_UPDATE_MS;
-    const session = new GameRoomSession(roomId, playerIds);
-
-    playerIds.forEach((playerId) => {
-      this.playerToRoom.set(playerId, roomId);
-    });
-
-    this.sessions.set(roomId, session);
-    session.start(tickRate, onTick, () => {
-      this.clearRoomPlayerIndex(roomId);
-      this.sessions.delete(roomId);
-      onGameEnd();
-    });
-
-    logEvent("GameSessionService", {
-      event: "START_GAME_LOOP",
-      result: "started",
-      roomId,
-      playerCount: playerIds.length,
-    });
-  }
-
-  public movePlayer(id: string, x: number, y: number): void {
-    const roomId = this.playerToRoom.get(id);
-    if (!roomId) {
-      logEvent("GameSessionService", {
-        event: "MOVE",
-        result: "ignored_player_not_in_session",
-        socketId: id,
-      });
-      return;
-    }
-
-    this.sessions.get(roomId)?.movePlayer(id, x, y);
-  }
-
-  public removePlayer(id: string): void {
-    const roomId = this.playerToRoom.get(id);
-    if (!roomId) {
-      logEvent("GameSessionService", {
-        event: "REMOVE_PLAYER",
-        result: "ignored_player_not_in_session",
-        socketId: id,
-      });
-      return;
-    }
-
-    const session = this.sessions.get(roomId);
-    if (!session) {
-      this.playerToRoom.delete(id);
-      return;
-    }
-
-    const removed = session.removePlayer(id);
-    this.playerToRoom.delete(id);
-
-    if (removed && session.isEmpty()) {
-      session.dispose();
-      this.sessions.delete(roomId);
-      logEvent("GameSessionService", {
-        event: "REMOVE_PLAYER",
-        result: "session_disposed_empty_room",
-        roomId,
-        socketId: id,
-      });
-    }
-  }
-
-  private clearRoomPlayerIndex(roomId: string): void {
-    Array.from(this.playerToRoom.entries()).forEach(([playerId, mappedRoomId]) => {
-      if (mappedRoomId === roomId) {
-        this.playerToRoom.delete(playerId);
-      }
-    });
-  }
-}
diff --git a/apps/server/src/domains/game/application/useCases/disconnectUseCase.ts b/apps/server/src/domains/game/application/useCases/disconnectUseCase.ts
index 49d886c..ce9ce89 100644
--- a/apps/server/src/domains/game/application/useCases/disconnectUseCase.ts
+++ b/apps/server/src/domains/game/application/useCases/disconnectUseCase.ts
@@ -2,17 +2,17 @@
 import { logEvent } from "@server/logging/logEvent";
 
 type DisconnectUseCaseParams = {
-  gameSessionManager: DisconnectPlayerPort;
+  gameManager: DisconnectPlayerPort;
   playerId: string;
   publishPlayerRemoved: (playerId: string) => void;
 };
 
 export const disconnectUseCase = ({
-  gameSessionManager,
+  gameManager,
   playerId,
   publishPlayerRemoved,
 }: DisconnectUseCaseParams) => {
-  gameSessionManager.removePlayer(playerId);
+  gameManager.removePlayer(playerId);
   publishPlayerRemoved(playerId);
   logEvent("GameUseCase", {
     event: "DISCONNECT",
diff --git a/apps/server/src/domains/game/application/useCases/movePlayerUseCase.ts b/apps/server/src/domains/game/application/useCases/movePlayerUseCase.ts
index 029f15d..9bcece1 100644
--- a/apps/server/src/domains/game/application/useCases/movePlayerUseCase.ts
+++ b/apps/server/src/domains/game/application/useCases/movePlayerUseCase.ts
@@ -2,15 +2,15 @@
 import type { MovePlayerPort } from "../ports/gameUseCasePorts";
 
 type MovePlayerUseCaseParams = {
-  gameSessionManager: MovePlayerPort;
+  gameManager: MovePlayerPort;
   playerId: string;
   move: playerTypes.MovePayload;
 };
 
 export const movePlayerUseCase = ({
-  gameSessionManager,
+  gameManager,
   playerId,
   move,
 }: MovePlayerUseCaseParams) => {
-  gameSessionManager.movePlayer(playerId, move.x, move.y);
+  gameManager.movePlayer(playerId, move.x, move.y);
 };
diff --git a/apps/server/src/domains/game/application/useCases/readyForGameUseCase.ts b/apps/server/src/domains/game/application/useCases/readyForGameUseCase.ts
index 21dd04e..067a1e2 100644
--- a/apps/server/src/domains/game/application/useCases/readyForGameUseCase.ts
+++ b/apps/server/src/domains/game/application/useCases/readyForGameUseCase.ts
@@ -5,7 +5,7 @@
 type ReadyForGameUseCaseParams = {
   socketId: string;
   roomId?: string;
-  gameSessionManager: ReadyForGamePort;
+  gameManager: ReadyForGamePort;
   publishCurrentPlayers: (players: playerTypes.PlayerData[]) => void;
   publishGameStart: (payload: { startTime: number }) => void;
 };
@@ -13,7 +13,7 @@
 export const readyForGameUseCase = ({
   socketId,
   roomId,
-  gameSessionManager,
+  gameManager,
   publishCurrentPlayers,
   publishGameStart,
 }: ReadyForGameUseCaseParams) => {
@@ -27,7 +27,7 @@
     return;
   }
 
-  const roomPlayers = gameSessionManager.getRoomPlayers(roomId);
+  const roomPlayers = gameManager.getRoomPlayers(roomId);
   publishCurrentPlayers(roomPlayers);
 
   logEvent("GameUseCase", {
@@ -38,7 +38,7 @@
     totalPlayers: roomPlayers.length,
   });
 
-  const startTime = gameSessionManager.getRoomStartTime(roomId);
+  const startTime = gameManager.getRoomStartTime(roomId);
   if (!startTime) {
     return;
   }
diff --git a/apps/server/src/domains/game/application/useCases/startGameUseCase.ts b/apps/server/src/domains/game/application/useCases/startGameUseCase.ts
index cc449c9..b8991db 100644
--- a/apps/server/src/domains/game/application/useCases/startGameUseCase.ts
+++ b/apps/server/src/domains/game/application/useCases/startGameUseCase.ts
@@ -6,7 +6,7 @@
 
 type StartGameUseCaseParams = {
   ownerId: string;
-  gameSessionManager: StartGamePort;
+  gameManager: StartGamePort;
   roomManager: RoomManager;
   publishUpdatePlayer: (roomId: string, playerData: playerTypes.PlayerData) => void;
   publishMapCellUpdates: (roomId: string, cellUpdates: gridMapTypes.CellUpdate[]) => void;
@@ -16,7 +16,7 @@
 
 export const startGameUseCase = ({
   ownerId,
-  gameSessionManager,
+  gameManager,
   roomManager,
   publishUpdatePlayer,
   publishMapCellUpdates,
@@ -55,7 +55,7 @@
 
   const playerIds = room.players.map((p: { id: string }) => p.id);
 
-  gameSessionManager.startRoomSession(
+  gameManager.startRoomSession(
     room.roomId,
     playerIds,
     (tickData) => {
@@ -79,6 +79,6 @@
     }
   );
 
-  const startTime = gameSessionManager.getRoomStartTime(room.roomId) || Date.now();
+  const startTime = gameManager.getRoomStartTime(room.roomId) || Date.now();
   publishGameStart(room.roomId, { startTime });
 };
diff --git a/apps/server/src/network/SocketManager.ts b/apps/server/src/network/SocketManager.ts
index 18ffa85..39372ed 100644
--- a/apps/server/src/network/SocketManager.ts
+++ b/apps/server/src/network/SocketManager.ts
@@ -10,12 +10,12 @@
 /** Socket.IOの接続ハンドラ登録を統括する */
 export class SocketManager {
   private io: Server;
-  private gameSessionManager: GameManager;
+  private gameManager: GameManager;
   private roomManager: RoomManager;
 
-  constructor(io: Server, gameSessionManager: GameManager, roomManager: RoomManager) {
+  constructor(io: Server, gameManager: GameManager, roomManager: RoomManager) {
     this.io = io;
-    this.gameSessionManager = gameSessionManager;
+    this.gameManager = gameManager;
     this.roomManager = roomManager;
   }
 
@@ -23,7 +23,7 @@
     // 接続時に必要な各ドメインハンドラを登録する
     registerConnectionHandlers({
       io: this.io,
-      gameSessionManager: this.gameSessionManager,
+      gameManager: this.gameManager,
       roomManager: this.roomManager,
     });
   }
diff --git a/apps/server/src/network/bootstrap/boot.ts b/apps/server/src/network/bootstrap/boot.ts
index 46a1ae2..29ba1ff 100644
--- a/apps/server/src/network/bootstrap/boot.ts
+++ b/apps/server/src/network/bootstrap/boot.ts
@@ -12,9 +12,9 @@
 export const boot = (httpServer: HttpServer) => {
   // ネットワーク層とドメイン層の依存を構築する
   const io = createIo(httpServer);
-  const gameSessionManager = new GameManager();
+  const gameManager = new GameManager();
   const roomManager = new RoomManager();
-  const socketManager = new SocketManager(io, gameSessionManager, roomManager);
+  const socketManager = new SocketManager(io, gameManager, roomManager);
 
   socketManager.initialize();
 };
diff --git a/apps/server/src/network/handlers/game/handleGameDisconnect.ts b/apps/server/src/network/handlers/game/handleGameDisconnect.ts
index bd28c55..0a7be66 100644
--- a/apps/server/src/network/handlers/game/handleGameDisconnect.ts
+++ b/apps/server/src/network/handlers/game/handleGameDisconnect.ts
@@ -10,14 +10,14 @@
 /** 切断したプレイヤーをゲーム管理から除外し通知する */
 export const handleGameDisconnect = (
   io: Server,
-  gameSessionManager: GameManager,
+  gameManager: GameManager,
   roomId: string | undefined,
   playerId: string
 ) => {
   const gameDisconnectPublisher = createGameDisconnectPublisher(io);
 
   disconnectUseCase({
-    gameSessionManager,
+    gameManager,
     playerId,
     publishPlayerRemoved: (removedPlayerId) => {
       if (!roomId) {
diff --git a/apps/server/src/network/handlers/game/registerGameHandlers.ts b/apps/server/src/network/handlers/game/registerGameHandlers.ts
index ff417c1..29d3511 100644
--- a/apps/server/src/network/handlers/game/registerGameHandlers.ts
+++ b/apps/server/src/network/handlers/game/registerGameHandlers.ts
@@ -20,7 +20,7 @@
 export const registerGameHandlers = (
   io: Server,
   socket: Socket,
-  gameSessionManager: GameManager,
+  gameManager: GameManager,
   roomManager: RoomManager
 ) => {
   const common = createCommonHandlerContext(io, socket);
@@ -47,7 +47,7 @@
   socket.on(protocol.SocketEvents.START_GAME, () => {
     startGameUseCase({
       ownerId: socket.id,
-      gameSessionManager,
+      gameManager,
       roomManager,
       publishUpdatePlayer: gamePublisher.publishUpdatePlayerToRoom,
       publishMapCellUpdates: gamePublisher.publishMapCellUpdatesToRoom,
@@ -63,7 +63,7 @@
     readyForGameUseCase({
       socketId: socket.id,
       roomId,
-      gameSessionManager,
+      gameManager,
       publishCurrentPlayers: gamePublisher.publishCurrentPlayersToSocket,
       publishGameStart: gamePublisher.publishGameStartToSocket,
     });
@@ -81,7 +81,7 @@
     }
 
     movePlayerUseCase({
-      gameSessionManager,
+      gameManager,
       playerId: socket.id,
       move: data,
     });
diff --git a/apps/server/src/network/handlers/registerConnectionHandlers.ts b/apps/server/src/network/handlers/registerConnectionHandlers.ts
index f6b4319..fa871f9 100644
--- a/apps/server/src/network/handlers/registerConnectionHandlers.ts
+++ b/apps/server/src/network/handlers/registerConnectionHandlers.ts
@@ -12,14 +12,14 @@
 
 type RegisterConnectionHandlersParams = {
   io: Server;
-  gameSessionManager: GameManager;
+  gameManager: GameManager;
   roomManager: RoomManager;
 };
 
 /** ソケット接続と切断イベントに対する共通ハンドラを登録する */
 export const registerConnectionHandlers = ({
   io,
-  gameSessionManager,
+  gameManager,
   roomManager,
 }: RegisterConnectionHandlersParams) => {
   io.on(protocol.SocketEvents.CONNECT, (socket: Socket) => {
@@ -31,7 +31,7 @@
     });
 
     registerRoomHandlers(io, socket, roomManager);
-    registerGameHandlers(io, socket, gameSessionManager, roomManager);
+    registerGameHandlers(io, socket, gameManager, roomManager);
 
     socket.on(protocol.SocketEvents.DISCONNECT, () => {
       // 切断ログ記録後にドメイン別の後処理を実行する
@@ -43,7 +43,7 @@
 
       const roomId = roomManager.getRoomByPlayerId(socket.id)?.roomId;
 
-      handleGameDisconnect(io, gameSessionManager, roomId, socket.id);
+      handleGameDisconnect(io, gameManager, roomId, socket.id);
       handleRoomDisconnect(io, socket, roomManager);
     });
   });