diff --git a/apps/server/src/domains/game/GameManager.ts b/apps/server/src/domains/game/GameManager.ts
index 332ef67..97ef4cf 100644
--- a/apps/server/src/domains/game/GameManager.ts
+++ b/apps/server/src/domains/game/GameManager.ts
@@ -1,68 +1,42 @@
-import { Player } from "./entities/Player.js";
-import { config } from "@repo/shared";
-import { MapStore } from "./states/MapStore";
-import { gridMapLogic } from "@repo/shared";
-import type { gridMapTypes } from "@repo/shared";
 import { GameLoop, type TickData } from "./GameLoop";
+import type { gridMapTypes } from "@repo/shared";
+import { Player } from "./entities/Player.js";
+import { PlayerRegistry } from "./application/services/PlayerRegistry";
+import { GameSessionService } from "./application/services/GameSessionService";
 
 // プレイヤー集合の生成・更新・参照管理クラス
 export class GameManager {
-  private players: Map<string, Player>;
-  private mapStore: MapStore;
-  private gameLoops: Map<string, GameLoop>; // NodeJS.Timeout から変更
-  private roomStartTimes: Map<string, number>;  // ルームごとのゲーム開始時間を保持する
+  private playerRegistry: PlayerRegistry;
+  private gameSessionService: GameSessionService;
 
   constructor() {
-    this.players = new Map();
-    this.mapStore = new MapStore();
-    this.gameLoops = new Map();
-    this.roomStartTimes = new Map();
+    this.playerRegistry = new PlayerRegistry();
+    this.gameSessionService = new GameSessionService(this.playerRegistry.getPlayersRef());
   }
 
   // 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.roomStartTimes.get(roomId);
+    return this.gameSessionService.getRoomStartTime(roomId);
   }
 
   // 新規プレイヤー登録と初期位置設定処理
   addPlayer(id: string): Player {
-    const player = new Player(id);
-    player.x = config.GAME_CONFIG.GRID_COLS / 2;
-    player.y = config.GAME_CONFIG.GRID_ROWS / 2;
-    this.players.set(id, player);
-    console.log("[GameManager] player added", { playerId: id, totalPlayers: this.players.size });
-    return player;
+    return this.playerRegistry.addPlayer(id);
   }
 
   // プレイヤー登録解除処理
   removePlayer(id: string) {
-    const existed = this.players.delete(id);
-    if (existed) {
-      console.log("[GameManager] player removed", { playerId: id, totalPlayers: this.players.size });
-    } else {
-      console.log("[GameManager] player remove ignored (not found)", { playerId: id });
-    }
+    this.playerRegistry.removePlayer(id);
   }
 
   // 指定IDプレイヤー参照取得
   getPlayer(id: string) {
-    return this.players.get(id);
+    return this.playerRegistry.getPlayer(id);
   }
 
   // 指定プレイヤー座標更新処理
   movePlayer(id: string, x: number, y: number) {
-    const player = this.players.get(id);
-    if (player) {
-      console.log(`Move Request -> ID:${id.slice(0,4)} x:${Math.round(x)} y:${Math.round(y)}`);
-      if (typeof x !== "number" || typeof y !== "number" || isNaN(x) || isNaN(y)) {
-        console.log("⚠️ 無効なデータなので無視しました");
-        return;
-      }
-      player.x = x;
-      player.y = y;
-    } else {
-      console.log("[GameManager] move ignored (player not found)", { playerId: id });
-    }
+    this.playerRegistry.movePlayer(id, x, y);
   }
 
   /**
@@ -77,67 +51,23 @@
     onTick: (data: TickData) => void,
     onGameEnd: () => void
   ) {
-    if (this.gameLoops.has(roomId)) {
-      console.log("[GameManager] startGameLoop ignored (already running)", { roomId });
-      return;
-    }
-
-    const tickRate = config.GAME_CONFIG.PLAYER_POSITION_UPDATE_MS;
-
-    // ループ開始時に、このルームの開始時刻を記憶する
-    this.roomStartTimes.set(roomId, Date.now());
-    
-    // GameLoopインスタンスを生成し、参照を渡す
-    const loop = new GameLoop(
-      roomId,
-      tickRate,
-      playerIds,
-      this.players,
-      this.mapStore,
-      onTick,
-      () => {
-        // GameLoopが終了した時の処理
-        this.roomStartTimes.delete(roomId);
-        this.gameLoops.delete(roomId);
-        onGameEnd(); // GameHandlerへ終了を伝える
-      }
-    );
-
-    loop.start();
-    this.gameLoops.set(roomId, loop);
-    console.log("[GameManager] game loop started", { roomId, playerCount: playerIds.length });
+    this.gameSessionService.startGameLoop(roomId, playerIds, onTick, onGameEnd);
   }
 
   /**
    * ゲームループを停止する
    */
   stopGameLoop(roomId: string) {
-    const loop = this.gameLoops.get(roomId);
-    if (loop) {
-      loop.stop();
-      this.gameLoops.delete(roomId);
-      this.roomStartTimes.delete(roomId); // 停止時も忘れずクリア
-      console.log("[GameManager] game loop stopped", { roomId });
-    } else {
-      console.log("[GameManager] stopGameLoop ignored (not running)", { roomId });
-    }
+    this.gameSessionService.stopGameLoop(roomId);
   }
 
   // 登録中全プレイヤー配列取得
   getAllPlayers() {
-    return Array.from(this.players.values());
+    return this.playerRegistry.getAllPlayers();
   }
 
   // 【一時的】移動したプレイヤーの足元を塗り、差分を返すメソッド
   public paintAndGetUpdates(playerId: string): gridMapTypes.CellUpdate[] {
-    const player = this.players.get(playerId);
-    if (!player) return [];
-
-    const gridIndex = gridMapLogic.getGridIndexFromPosition(player.x, player.y);
-    if (gridIndex !== null) {
-      this.mapStore.paintCell(gridIndex, player.teamId);
-    }
-
-    return this.mapStore.getAndClearUpdates();
+    return this.gameSessionService.paintAndGetUpdates(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
new file mode 100644
index 0000000..ab33e56
--- /dev/null
+++ b/apps/server/src/domains/game/application/services/GameSessionService.ts
@@ -0,0 +1,78 @@
+import { config, gridMapLogic } from "@repo/shared";
+import type { gridMapTypes } from "@repo/shared";
+import { GameLoop, type TickData } from "../../GameLoop";
+import { Player } from "../../entities/Player.js";
+import { MapStore } from "../../states/MapStore";
+
+export class GameSessionService {
+  private mapStore: MapStore;
+  private gameLoops: Map<string, GameLoop>;
+  private roomStartTimes: Map<string, number>;
+
+  constructor(private players: Map<string, Player>) {
+    this.mapStore = new MapStore();
+    this.gameLoops = new Map();
+    this.roomStartTimes = new Map();
+  }
+
+  public getRoomStartTime(roomId: string): number | undefined {
+    return this.roomStartTimes.get(roomId);
+  }
+
+  public startGameLoop(
+    roomId: string,
+    playerIds: string[],
+    onTick: (data: TickData) => void,
+    onGameEnd: () => void
+  ) {
+    if (this.gameLoops.has(roomId)) {
+      console.log("[GameManager] startGameLoop ignored (already running)", { roomId });
+      return;
+    }
+
+    const tickRate = config.GAME_CONFIG.PLAYER_POSITION_UPDATE_MS;
+    this.roomStartTimes.set(roomId, Date.now());
+
+    const loop = new GameLoop(
+      roomId,
+      tickRate,
+      playerIds,
+      this.players,
+      this.mapStore,
+      onTick,
+      () => {
+        this.roomStartTimes.delete(roomId);
+        this.gameLoops.delete(roomId);
+        onGameEnd();
+      }
+    );
+
+    loop.start();
+    this.gameLoops.set(roomId, loop);
+    console.log("[GameManager] game loop started", { roomId, playerCount: playerIds.length });
+  }
+
+  public stopGameLoop(roomId: string) {
+    const loop = this.gameLoops.get(roomId);
+    if (loop) {
+      loop.stop();
+      this.gameLoops.delete(roomId);
+      this.roomStartTimes.delete(roomId);
+      console.log("[GameManager] game loop stopped", { roomId });
+    } else {
+      console.log("[GameManager] stopGameLoop ignored (not running)", { roomId });
+    }
+  }
+
+  public paintAndGetUpdates(playerId: string): gridMapTypes.CellUpdate[] {
+    const player = this.players.get(playerId);
+    if (!player) return [];
+
+    const gridIndex = gridMapLogic.getGridIndexFromPosition(player.x, player.y);
+    if (gridIndex !== null) {
+      this.mapStore.paintCell(gridIndex, player.teamId);
+    }
+
+    return this.mapStore.getAndClearUpdates();
+  }
+}
diff --git a/apps/server/src/domains/game/application/services/PlayerRegistry.ts b/apps/server/src/domains/game/application/services/PlayerRegistry.ts
new file mode 100644
index 0000000..5233ce4
--- /dev/null
+++ b/apps/server/src/domains/game/application/services/PlayerRegistry.ts
@@ -0,0 +1,55 @@
+import { config } from "@repo/shared";
+import { Player } from "../../entities/Player.js";
+
+export class PlayerRegistry {
+  private players: Map<string, Player>;
+
+  constructor() {
+    this.players = new Map();
+  }
+
+  public addPlayer(id: string): Player {
+    const player = new Player(id);
+    player.x = config.GAME_CONFIG.GRID_COLS / 2;
+    player.y = config.GAME_CONFIG.GRID_ROWS / 2;
+    this.players.set(id, player);
+    console.log("[GameManager] player added", { playerId: id, totalPlayers: this.players.size });
+    return player;
+  }
+
+  public removePlayer(id: string) {
+    const existed = this.players.delete(id);
+    if (existed) {
+      console.log("[GameManager] player removed", { playerId: id, totalPlayers: this.players.size });
+    } else {
+      console.log("[GameManager] player remove ignored (not found)", { playerId: id });
+    }
+  }
+
+  public getPlayer(id: string): Player | undefined {
+    return this.players.get(id);
+  }
+
+  public movePlayer(id: string, x: number, y: number) {
+    const player = this.players.get(id);
+    if (player) {
+      console.log(`Move Request -> ID:${id.slice(0, 4)} x:${Math.round(x)} y:${Math.round(y)}`);
+      if (typeof x !== "number" || typeof y !== "number" || isNaN(x) || isNaN(y)) {
+        console.log("⚠️ 無効なデータなので無視しました");
+        return;
+      }
+      player.x = x;
+      player.y = y;
+    } else {
+      console.log("[GameManager] move ignored (player not found)", { playerId: id });
+    }
+  }
+
+  public getAllPlayers(): Player[] {
+    return Array.from(this.players.values());
+  }
+
+  public getPlayersRef(): Map<string, Player> {
+    return this.players;
+  }
+}