diff --git a/apps/server/src/managers/GameManager.ts b/apps/server/src/managers/GameManager.ts
new file mode 100644
index 0000000..a69454a
--- /dev/null
+++ b/apps/server/src/managers/GameManager.ts
@@ -0,0 +1,38 @@
+// src/managers/GameManager.ts
+import { Player } from "../entities/Player.js";
+
+export class GameManager {
+  // IDをキーにしてプレイヤーを保存する
+  private players: Map<string, Player>;
+
+  constructor() {
+    this.players = new Map();
+  }
+
+  // プレイヤー追加
+  addPlayer(id: string): Player {
+    const player = new Player(id);
+    this.players.set(id, player);
+    return player;
+  }
+
+  // プレイヤー削除
+  removePlayer(id: string) {
+    this.players.delete(id);
+  }
+
+  // プレイヤー移動
+  movePlayer(id: string, x: number, y: number) {
+    const player = this.players.get(id);
+    if (player) {
+      player.x = x;
+      player.y = y;
+    }
+  }
+
+  // 全プレイヤーのリストを返す（通信で送るため）
+  getAllPlayers() {
+    // Mapを配列({id, x, y, color}[])に変換
+    return Array.from(this.players.values());
+  }
+}
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