diff --git a/apps/server/src/domains/game/application/useCases/disconnectUseCase.ts b/apps/server/src/domains/game/application/useCases/disconnectUseCase.ts
new file mode 100644
index 0000000..1db69d0
--- /dev/null
+++ b/apps/server/src/domains/game/application/useCases/disconnectUseCase.ts
@@ -0,0 +1,20 @@
+import { protocol } from "@repo/shared";
+import type { DisconnectPlayerPort } from "../ports/gameUseCasePorts";
+
+type EmitToAll = (event: string, payload?: unknown) => void;
+
+type DisconnectUseCaseParams = {
+  gameManager: DisconnectPlayerPort;
+  playerId: string;
+  emitToAll: EmitToAll;
+};
+
+export const disconnectUseCase = ({
+  gameManager,
+  playerId,
+  emitToAll,
+}: DisconnectUseCaseParams) => {
+  gameManager.removePlayer(playerId);
+  emitToAll(protocol.SocketEvents.REMOVE_PLAYER, playerId);
+  console.log("[GameHandler] player removed", { playerId });
+};
diff --git a/apps/server/src/domains/game/application/useCases/executeDisconnectUseCase.ts b/apps/server/src/domains/game/application/useCases/executeDisconnectUseCase.ts
deleted file mode 100644
index 1db69d0..0000000
--- a/apps/server/src/domains/game/application/useCases/executeDisconnectUseCase.ts
+++ /dev/null
@@ -1,20 +0,0 @@
-import { protocol } from "@repo/shared";
-import type { DisconnectPlayerPort } from "../ports/gameUseCasePorts";
-
-type EmitToAll = (event: string, payload?: unknown) => void;
-
-type DisconnectUseCaseParams = {
-  gameManager: DisconnectPlayerPort;
-  playerId: string;
-  emitToAll: EmitToAll;
-};
-
-export const disconnectUseCase = ({
-  gameManager,
-  playerId,
-  emitToAll,
-}: DisconnectUseCaseParams) => {
-  gameManager.removePlayer(playerId);
-  emitToAll(protocol.SocketEvents.REMOVE_PLAYER, playerId);
-  console.log("[GameHandler] player removed", { playerId });
-};
diff --git a/apps/server/src/domains/game/application/useCases/executeMovePlayerUseCase.ts b/apps/server/src/domains/game/application/useCases/executeMovePlayerUseCase.ts
deleted file mode 100644
index 9bcece1..0000000
--- a/apps/server/src/domains/game/application/useCases/executeMovePlayerUseCase.ts
+++ /dev/null
@@ -1,16 +0,0 @@
-import type { playerTypes } from "@repo/shared";
-import type { MovePlayerPort } from "../ports/gameUseCasePorts";
-
-type MovePlayerUseCaseParams = {
-  gameManager: MovePlayerPort;
-  playerId: string;
-  move: playerTypes.MovePayload;
-};
-
-export const movePlayerUseCase = ({
-  gameManager,
-  playerId,
-  move,
-}: MovePlayerUseCaseParams) => {
-  gameManager.movePlayer(playerId, move.x, move.y);
-};
diff --git a/apps/server/src/domains/game/application/useCases/executePingUseCase.ts b/apps/server/src/domains/game/application/useCases/executePingUseCase.ts
deleted file mode 100644
index 0ef9f54..0000000
--- a/apps/server/src/domains/game/application/useCases/executePingUseCase.ts
+++ /dev/null
@@ -1,18 +0,0 @@
-import { protocol } from "@repo/shared";
-
-type EmitToSocket = (event: string, payload?: unknown) => void;
-
-type PingUseCaseParams = {
-  clientTime: number;
-  emitToSocket: EmitToSocket;
-};
-
-export const pingUseCase = ({
-  clientTime,
-  emitToSocket,
-}: PingUseCaseParams) => {
-  emitToSocket(protocol.SocketEvents.PONG, {
-    clientTime,
-    serverTime: Date.now(),
-  });
-};
diff --git a/apps/server/src/domains/game/application/useCases/executeReadyForGameUseCase.ts b/apps/server/src/domains/game/application/useCases/executeReadyForGameUseCase.ts
deleted file mode 100644
index 92ab796..0000000
--- a/apps/server/src/domains/game/application/useCases/executeReadyForGameUseCase.ts
+++ /dev/null
@@ -1,43 +0,0 @@
-import { protocol } from "@repo/shared";
-import type { ReadyForGamePort } from "../ports/gameUseCasePorts";
-
-type EmitToSocket = (event: string, payload?: unknown) => void;
-
-type ReadyForGameUseCaseParams = {
-  socketId: string;
-  roomId?: string;
-  gameManager: ReadyForGamePort;
-  emitToSocket: EmitToSocket;
-};
-
-export const readyForGameUseCase = ({
-  socketId,
-  roomId,
-  gameManager,
-  emitToSocket,
-}: ReadyForGameUseCaseParams) => {
-  const allPlayers = gameManager.getAllPlayers();
-  emitToSocket(protocol.SocketEvents.CURRENT_PLAYERS, allPlayers);
-
-  console.log("[GameHandler] READY_FOR_GAME received", {
-    socketId,
-    totalPlayers: allPlayers.length,
-  });
-
-  if (!roomId) {
-    console.log("[GameHandler] READY_FOR_GAME missing roomId", { socketId });
-    return;
-  }
-
-  const startTime = gameManager.getRoomStartTime(roomId);
-  if (!startTime) {
-    return;
-  }
-
-  emitToSocket(protocol.SocketEvents.GAME_START, { startTime });
-  console.log("[GameHandler] GAME_START sent to ready client", {
-    socketId,
-    roomId,
-    startTime,
-  });
-};
diff --git a/apps/server/src/domains/game/application/useCases/executeStartGameUseCase.ts b/apps/server/src/domains/game/application/useCases/executeStartGameUseCase.ts
deleted file mode 100644
index 41b2772..0000000
--- a/apps/server/src/domains/game/application/useCases/executeStartGameUseCase.ts
+++ /dev/null
@@ -1,66 +0,0 @@
-import { protocol, roomConsts } from "@repo/shared";
-import { RoomManager } from "@server/domains/room/RoomManager";
-import type { StartGamePort } from "../ports/gameUseCasePorts";
-
-type EmitToRoom = (roomId: string, event: string, payload?: unknown) => void;
-
-type StartGameUseCaseParams = {
-  ownerId: string;
-  gameManager: StartGamePort;
-  roomManager: RoomManager;
-  emitToRoom: EmitToRoom;
-};
-
-export const startGameUseCase = ({
-  ownerId,
-  gameManager,
-  roomManager,
-  emitToRoom,
-}: StartGameUseCaseParams) => {
-  const room = roomManager.getRoomByOwnerId(ownerId);
-  if (!room) {
-    console.log("[GameHandler] START_GAME ignored (no room)", { socketId: ownerId });
-    return;
-  }
-
-  if (room.status === roomConsts.RoomPhase.PLAYING) {
-    console.log("[GameHandler] START_GAME ignored (already playing)", { roomId: room.roomId });
-    return;
-  }
-
-  console.log("[GameHandler] START_GAME accepted", {
-    roomId: room.roomId,
-    ownerId,
-    totalPlayers: room.players.length,
-  });
-
-  room.status = roomConsts.RoomPhase.PLAYING;
-
-  const playerIds = room.players.map((p: { id: string }) => p.id);
-
-  room.players.forEach((p: { id: string }) => {
-    gameManager.addPlayer(p.id);
-  });
-
-  gameManager.startGameLoop(
-    room.roomId,
-    playerIds,
-    (tickData) => {
-      tickData.players.forEach((playerData) => {
-        emitToRoom(room.roomId, protocol.SocketEvents.UPDATE_PLAYER, playerData);
-      });
-
-      if (tickData.cellUpdates.length > 0) {
-        emitToRoom(room.roomId, protocol.SocketEvents.UPDATE_MAP_CELLS, tickData.cellUpdates);
-      }
-    },
-    () => {
-      console.log(`[GameHandler] ルーム ${room.roomId} のゲームが終了しました (3分経過)`);
-      emitToRoom(room.roomId, protocol.SocketEvents.GAME_END);
-      room.status = roomConsts.RoomPhase.WAITING;
-    }
-  );
-
-  const startTime = gameManager.getRoomStartTime(room.roomId) || Date.now();
-  emitToRoom(room.roomId, protocol.SocketEvents.GAME_START, { startTime });
-};
diff --git a/apps/server/src/domains/game/application/useCases/movePlayerUseCase.ts b/apps/server/src/domains/game/application/useCases/movePlayerUseCase.ts
new file mode 100644
index 0000000..9bcece1
--- /dev/null
+++ b/apps/server/src/domains/game/application/useCases/movePlayerUseCase.ts
@@ -0,0 +1,16 @@
+import type { playerTypes } from "@repo/shared";
+import type { MovePlayerPort } from "../ports/gameUseCasePorts";
+
+type MovePlayerUseCaseParams = {
+  gameManager: MovePlayerPort;
+  playerId: string;
+  move: playerTypes.MovePayload;
+};
+
+export const movePlayerUseCase = ({
+  gameManager,
+  playerId,
+  move,
+}: MovePlayerUseCaseParams) => {
+  gameManager.movePlayer(playerId, move.x, move.y);
+};
diff --git a/apps/server/src/domains/game/application/useCases/pingUseCase.ts b/apps/server/src/domains/game/application/useCases/pingUseCase.ts
new file mode 100644
index 0000000..0ef9f54
--- /dev/null
+++ b/apps/server/src/domains/game/application/useCases/pingUseCase.ts
@@ -0,0 +1,18 @@
+import { protocol } from "@repo/shared";
+
+type EmitToSocket = (event: string, payload?: unknown) => void;
+
+type PingUseCaseParams = {
+  clientTime: number;
+  emitToSocket: EmitToSocket;
+};
+
+export const pingUseCase = ({
+  clientTime,
+  emitToSocket,
+}: PingUseCaseParams) => {
+  emitToSocket(protocol.SocketEvents.PONG, {
+    clientTime,
+    serverTime: Date.now(),
+  });
+};
diff --git a/apps/server/src/domains/game/application/useCases/readyForGameUseCase.ts b/apps/server/src/domains/game/application/useCases/readyForGameUseCase.ts
new file mode 100644
index 0000000..92ab796
--- /dev/null
+++ b/apps/server/src/domains/game/application/useCases/readyForGameUseCase.ts
@@ -0,0 +1,43 @@
+import { protocol } from "@repo/shared";
+import type { ReadyForGamePort } from "../ports/gameUseCasePorts";
+
+type EmitToSocket = (event: string, payload?: unknown) => void;
+
+type ReadyForGameUseCaseParams = {
+  socketId: string;
+  roomId?: string;
+  gameManager: ReadyForGamePort;
+  emitToSocket: EmitToSocket;
+};
+
+export const readyForGameUseCase = ({
+  socketId,
+  roomId,
+  gameManager,
+  emitToSocket,
+}: ReadyForGameUseCaseParams) => {
+  const allPlayers = gameManager.getAllPlayers();
+  emitToSocket(protocol.SocketEvents.CURRENT_PLAYERS, allPlayers);
+
+  console.log("[GameHandler] READY_FOR_GAME received", {
+    socketId,
+    totalPlayers: allPlayers.length,
+  });
+
+  if (!roomId) {
+    console.log("[GameHandler] READY_FOR_GAME missing roomId", { socketId });
+    return;
+  }
+
+  const startTime = gameManager.getRoomStartTime(roomId);
+  if (!startTime) {
+    return;
+  }
+
+  emitToSocket(protocol.SocketEvents.GAME_START, { startTime });
+  console.log("[GameHandler] GAME_START sent to ready client", {
+    socketId,
+    roomId,
+    startTime,
+  });
+};
diff --git a/apps/server/src/domains/game/application/useCases/startGameUseCase.ts b/apps/server/src/domains/game/application/useCases/startGameUseCase.ts
new file mode 100644
index 0000000..41b2772
--- /dev/null
+++ b/apps/server/src/domains/game/application/useCases/startGameUseCase.ts
@@ -0,0 +1,66 @@
+import { protocol, roomConsts } from "@repo/shared";
+import { RoomManager } from "@server/domains/room/RoomManager";
+import type { StartGamePort } from "../ports/gameUseCasePorts";
+
+type EmitToRoom = (roomId: string, event: string, payload?: unknown) => void;
+
+type StartGameUseCaseParams = {
+  ownerId: string;
+  gameManager: StartGamePort;
+  roomManager: RoomManager;
+  emitToRoom: EmitToRoom;
+};
+
+export const startGameUseCase = ({
+  ownerId,
+  gameManager,
+  roomManager,
+  emitToRoom,
+}: StartGameUseCaseParams) => {
+  const room = roomManager.getRoomByOwnerId(ownerId);
+  if (!room) {
+    console.log("[GameHandler] START_GAME ignored (no room)", { socketId: ownerId });
+    return;
+  }
+
+  if (room.status === roomConsts.RoomPhase.PLAYING) {
+    console.log("[GameHandler] START_GAME ignored (already playing)", { roomId: room.roomId });
+    return;
+  }
+
+  console.log("[GameHandler] START_GAME accepted", {
+    roomId: room.roomId,
+    ownerId,
+    totalPlayers: room.players.length,
+  });
+
+  room.status = roomConsts.RoomPhase.PLAYING;
+
+  const playerIds = room.players.map((p: { id: string }) => p.id);
+
+  room.players.forEach((p: { id: string }) => {
+    gameManager.addPlayer(p.id);
+  });
+
+  gameManager.startGameLoop(
+    room.roomId,
+    playerIds,
+    (tickData) => {
+      tickData.players.forEach((playerData) => {
+        emitToRoom(room.roomId, protocol.SocketEvents.UPDATE_PLAYER, playerData);
+      });
+
+      if (tickData.cellUpdates.length > 0) {
+        emitToRoom(room.roomId, protocol.SocketEvents.UPDATE_MAP_CELLS, tickData.cellUpdates);
+      }
+    },
+    () => {
+      console.log(`[GameHandler] ルーム ${room.roomId} のゲームが終了しました (3分経過)`);
+      emitToRoom(room.roomId, protocol.SocketEvents.GAME_END);
+      room.status = roomConsts.RoomPhase.WAITING;
+    }
+  );
+
+  const startTime = gameManager.getRoomStartTime(room.roomId) || Date.now();
+  emitToRoom(room.roomId, protocol.SocketEvents.GAME_START, { startTime });
+};
diff --git a/apps/server/src/domains/room/application/useCases/executeJoinRoomUseCase.ts b/apps/server/src/domains/room/application/useCases/executeJoinRoomUseCase.ts
deleted file mode 100644
index 2123b35..0000000
--- a/apps/server/src/domains/room/application/useCases/executeJoinRoomUseCase.ts
+++ /dev/null
@@ -1,31 +0,0 @@
-import { protocol } from "@repo/shared";
-import type { roomTypes } from "@repo/shared";
-import type { JoinRoomPort } from "../ports/roomUseCasePorts";
-
-type EmitToRoom = (roomId: string, event: string, payload?: unknown) => void;
-
-type JoinRoomUseCaseParams = {
-  roomManager: JoinRoomPort;
-  socketId: string;
-  data: roomTypes.JoinRoomPayload;
-  emitToRoom: EmitToRoom;
-};
-
-export const joinRoomUseCase = ({
-  roomManager,
-  socketId,
-  data,
-  emitToRoom,
-}: JoinRoomUseCaseParams) => {
-  const { roomId, playerName } = data;
-  console.log("[RoomHandler] JOIN_ROOM received", { roomId, socketId, playerName });
-
-  const room = roomManager.addPlayerToRoom(roomId, socketId, playerName);
-
-  emitToRoom(roomId, protocol.SocketEvents.ROOM_UPDATE, room);
-  console.log("[RoomHandler] ROOM_UPDATE emitted", {
-    roomId,
-    ownerId: room.ownerId,
-    totalPlayers: room.players.length,
-  });
-};
diff --git a/apps/server/src/domains/room/application/useCases/executeRoomDisconnectUseCase.ts b/apps/server/src/domains/room/application/useCases/executeRoomDisconnectUseCase.ts
deleted file mode 100644
index be33326..0000000
--- a/apps/server/src/domains/room/application/useCases/executeRoomDisconnectUseCase.ts
+++ /dev/null
@@ -1,31 +0,0 @@
-import { protocol } from "@repo/shared";
-import type { DisconnectRoomPort } from "../ports/roomUseCasePorts";
-
-type EmitToRoom = (roomId: string, event: string, payload?: unknown) => void;
-
-type RoomDisconnectUseCaseParams = {
-  roomManager: DisconnectRoomPort;
-  socketId: string;
-  emitToRoom: EmitToRoom;
-};
-
-export const roomDisconnectUseCase = ({
-  roomManager,
-  socketId,
-  emitToRoom,
-}: RoomDisconnectUseCaseParams) => {
-  const updatedRooms = roomManager.removePlayer(socketId);
-  console.log("[RoomHandler] disconnect cleanup", {
-    socketId,
-    updatedRoomCount: updatedRooms.length,
-  });
-
-  updatedRooms.forEach((room) => {
-    emitToRoom(room.roomId, protocol.SocketEvents.ROOM_UPDATE, room);
-    console.log("[RoomHandler] ROOM_UPDATE emitted", {
-      roomId: room.roomId,
-      ownerId: room.ownerId,
-      totalPlayers: room.players.length,
-    });
-  });
-};
diff --git a/apps/server/src/domains/room/application/useCases/joinRoomUseCase.ts b/apps/server/src/domains/room/application/useCases/joinRoomUseCase.ts
new file mode 100644
index 0000000..2123b35
--- /dev/null
+++ b/apps/server/src/domains/room/application/useCases/joinRoomUseCase.ts
@@ -0,0 +1,31 @@
+import { protocol } from "@repo/shared";
+import type { roomTypes } from "@repo/shared";
+import type { JoinRoomPort } from "../ports/roomUseCasePorts";
+
+type EmitToRoom = (roomId: string, event: string, payload?: unknown) => void;
+
+type JoinRoomUseCaseParams = {
+  roomManager: JoinRoomPort;
+  socketId: string;
+  data: roomTypes.JoinRoomPayload;
+  emitToRoom: EmitToRoom;
+};
+
+export const joinRoomUseCase = ({
+  roomManager,
+  socketId,
+  data,
+  emitToRoom,
+}: JoinRoomUseCaseParams) => {
+  const { roomId, playerName } = data;
+  console.log("[RoomHandler] JOIN_ROOM received", { roomId, socketId, playerName });
+
+  const room = roomManager.addPlayerToRoom(roomId, socketId, playerName);
+
+  emitToRoom(roomId, protocol.SocketEvents.ROOM_UPDATE, room);
+  console.log("[RoomHandler] ROOM_UPDATE emitted", {
+    roomId,
+    ownerId: room.ownerId,
+    totalPlayers: room.players.length,
+  });
+};
diff --git a/apps/server/src/domains/room/application/useCases/roomDisconnectUseCase.ts b/apps/server/src/domains/room/application/useCases/roomDisconnectUseCase.ts
new file mode 100644
index 0000000..be33326
--- /dev/null
+++ b/apps/server/src/domains/room/application/useCases/roomDisconnectUseCase.ts
@@ -0,0 +1,31 @@
+import { protocol } from "@repo/shared";
+import type { DisconnectRoomPort } from "../ports/roomUseCasePorts";
+
+type EmitToRoom = (roomId: string, event: string, payload?: unknown) => void;
+
+type RoomDisconnectUseCaseParams = {
+  roomManager: DisconnectRoomPort;
+  socketId: string;
+  emitToRoom: EmitToRoom;
+};
+
+export const roomDisconnectUseCase = ({
+  roomManager,
+  socketId,
+  emitToRoom,
+}: RoomDisconnectUseCaseParams) => {
+  const updatedRooms = roomManager.removePlayer(socketId);
+  console.log("[RoomHandler] disconnect cleanup", {
+    socketId,
+    updatedRoomCount: updatedRooms.length,
+  });
+
+  updatedRooms.forEach((room) => {
+    emitToRoom(room.roomId, protocol.SocketEvents.ROOM_UPDATE, room);
+    console.log("[RoomHandler] ROOM_UPDATE emitted", {
+      roomId: room.roomId,
+      ownerId: room.ownerId,
+      totalPlayers: room.players.length,
+    });
+  });
+};