diff --git a/apps/client/src/network/handlers/GameHandler.ts b/apps/client/src/network/handlers/GameHandler.ts
index e87bf04..0360d91 100644
--- a/apps/client/src/network/handlers/GameHandler.ts
+++ b/apps/client/src/network/handlers/GameHandler.ts
@@ -5,7 +5,7 @@
  */
 import type { Socket } from "socket.io-client";
 import { protocol } from "@repo/shared";
-import type { playerTypes, gridMapTypes } from "@repo/shared";
+import type { playerTypes, gridMapTypes, UpdatePlayersPayload } from "@repo/shared";
 
 /** ゲームシーンが利用するソケット操作の契約 */
 export type GameHandler = {
@@ -13,8 +13,8 @@
   offCurrentPlayers: (callback: (players: playerTypes.PlayerData[] | Record<string, playerTypes.PlayerData>) => void) => void;
   onNewPlayer: (callback: (player: playerTypes.PlayerData) => void) => void;
   offNewPlayer: (callback: (player: playerTypes.PlayerData) => void) => void;
-  onUpdatePlayers: (callback: (players: playerTypes.PlayerData[]) => void) => void;
-  offUpdatePlayers: (callback: (players: playerTypes.PlayerData[]) => void) => void;
+  onUpdatePlayers: (callback: (players: UpdatePlayersPayload) => void) => void;
+  offUpdatePlayers: (callback: (players: UpdatePlayersPayload) => void) => void;
   onRemovePlayer: (callback: (id: string) => void) => void;
   offRemovePlayer: (callback: (id: string) => void) => void;
   onUpdateMapCells: (callback: (updates: gridMapTypes.CellUpdate[]) => void) => void;
diff --git a/apps/server/src/domains/game/GameManager.ts b/apps/server/src/domains/game/GameManager.ts
index c94a91b..34a577b 100644
--- a/apps/server/src/domains/game/GameManager.ts
+++ b/apps/server/src/domains/game/GameManager.ts
@@ -2,7 +2,7 @@
  * GameManager
  * ゲームセッション集合の生成，更新，参照管理を統括する
  */
-import { type TickData } from "./loop/GameLoop";
+import type { gameTypes } from "@repo/shared";
 import { Player } from "./entities/player/Player.js";
 import { GameRoomSession } from "./application/services/GameRoomSession";
 import { GameSessionLifecycleService } from "./application/services/GameSessionLifecycleService";
@@ -49,7 +49,7 @@
   startRoomSession(
     roomId: string, 
     playerIds: string[], 
-    onTick: (data: TickData) => void,
+    onTick: (data: gameTypes.TickData) => void,
     onGameEnd: () => void
   ) {
     this.lifecycleService.startRoomSession(roomId, playerIds, onTick, onGameEnd);
diff --git a/apps/server/src/domains/game/application/ports/gameUseCasePorts.ts b/apps/server/src/domains/game/application/ports/gameUseCasePorts.ts
index 4d03233..617d04b 100644
--- a/apps/server/src/domains/game/application/ports/gameUseCasePorts.ts
+++ b/apps/server/src/domains/game/application/ports/gameUseCasePorts.ts
@@ -2,15 +2,14 @@
  * gameUseCasePorts
  * ゲーム系ユースケースが利用する入力ポートと出力ポートの契約を定義する
  */
-import type { TickData } from "../../loop/GameLoop";
-import type { gridMapTypes, playerTypes, roomTypes } from "@repo/shared";
+import type { gameTypes, gridMapTypes, playerTypes, roomTypes, UpdatePlayersPayload } from "@repo/shared";
 
 /** ゲーム開始ユースケースが利用するゲーム管理入力ポート */
 export interface StartGamePort {
   startRoomSession(
     roomId: string,
     playerIds: string[],
-    onTick: (data: TickData) => void,
+    onTick: (data: gameTypes.TickData) => void,
     onGameEnd: () => void
   ): void;
   getRoomStartTime(roomId: string): number | undefined;
@@ -49,7 +48,7 @@
   publishPongToSocket(payload: { clientTime: number; serverTime: number }): void;
   publishUpdatePlayersToRoom(
     roomId: roomTypes.Room["roomId"],
-    players: playerTypes.PlayerData[]
+    players: UpdatePlayersPayload
   ): void;
   publishMapCellUpdatesToRoom(
     roomId: roomTypes.Room["roomId"],
diff --git a/apps/server/src/domains/game/application/services/GameRoomSession.ts b/apps/server/src/domains/game/application/services/GameRoomSession.ts
index dea7e1f..efe7e8e 100644
--- a/apps/server/src/domains/game/application/services/GameRoomSession.ts
+++ b/apps/server/src/domains/game/application/services/GameRoomSession.ts
@@ -3,7 +3,8 @@
  * 1ルーム分のゲーム進行状態とゲームループ実行を管理する
  */
 import { logEvent } from "@server/logging/logEvent";
-import { GameLoop, type TickData } from "../../loop/GameLoop";
+import type { gameTypes } from "@repo/shared";
+import { GameLoop } from "../../loop/GameLoop";
 import { Player } from "../../entities/player/Player.js";
 import { MapStore } from "../../entities/map/MapStore";
 import { createSpawnedPlayer } from "../../entities/player/playerSpawn.js";
@@ -31,7 +32,7 @@
 
   public start(
     tickRate: number,
-    onTick: (data: TickData) => void,
+    onTick: (data: gameTypes.TickData) => void,
     onGameEnd: () => void
   ): void {
     if (this.gameLoop) {
diff --git a/apps/server/src/domains/game/application/services/GameSessionLifecycleService.ts b/apps/server/src/domains/game/application/services/GameSessionLifecycleService.ts
index 52261b6..7cc15e3 100644
--- a/apps/server/src/domains/game/application/services/GameSessionLifecycleService.ts
+++ b/apps/server/src/domains/game/application/services/GameSessionLifecycleService.ts
@@ -3,7 +3,7 @@
  * ゲームセッションの開始，参照，終了時クリーンアップを管理する
  */
 import { config } from "@repo/shared";
-import { type TickData } from "../../loop/GameLoop";
+import type { gameTypes } from "@repo/shared";
 import { logEvent } from "@server/logging/logEvent";
 import { GameRoomSession } from "./GameRoomSession";
 
@@ -30,7 +30,7 @@
   public startRoomSession(
     roomId: string,
     playerIds: string[],
-    onTick: (data: TickData) => void,
+    onTick: (data: gameTypes.TickData) => void,
     onGameEnd: () => void
   ) {
     if (this.sessions.has(roomId)) {
diff --git a/apps/server/src/domains/game/loop/GameLoop.ts b/apps/server/src/domains/game/loop/GameLoop.ts
index e34af53..0ddb36e 100644
--- a/apps/server/src/domains/game/loop/GameLoop.ts
+++ b/apps/server/src/domains/game/loop/GameLoop.ts
@@ -6,21 +6,9 @@
 import { MapStore } from "../entities/map/MapStore";
 import { getPlayerGridIndex } from "../entities/player/playerPosition.js";
 import { config } from "@repo/shared";
-import type { gridMapTypes } from "@repo/shared";
+import type { gameTypes } from "@repo/shared";
 import { logEvent } from "@server/logging/logEvent";
 
-// コールバックで渡すデータの型定義
-/** 1ティック分のプレイヤー情報とマップ差分を表すデータ */
-export interface TickData {
-  playerUpdates: {
-    id: string;
-    x: number;
-    y: number;
-    teamId: number;
-  }[];
-  cellUpdates: gridMapTypes.CellUpdate[];
-}
-
 /** ルーム内ゲーム進行を定周期で実行するループ管理クラス */
 export class GameLoop {
   private loopId: NodeJS.Timeout | null = null;
@@ -29,14 +17,14 @@
   private endMonotonicTimeMs: number = 0;
   private nextTickAtMs: number = 0;
   private readonly maxCatchUpTicks: number = 3;
-  private lastSentPlayers: Map<string, TickData["playerUpdates"][number]> = new Map();
+  private lastSentPlayers: Map<string, gameTypes.TickData["playerUpdates"][number]> = new Map();
 
   constructor(
     private roomId: string,
     private tickRate: number,
     private players: Map<string, Player>,
     private mapStore: MapStore,
-    private onTick: (data: TickData) => void,
+    private onTick: (data: gameTypes.TickData) => void,
     private onGameEnd: () => void   // ゲーム終了時のコールバック
   ) {}
 
@@ -103,7 +91,7 @@
   }
 
   private processSingleTick(): void {
-    const changedPlayers: TickData["playerUpdates"] = [];
+    const changedPlayers: gameTypes.TickData["playerUpdates"] = [];
 
     // 1. 各プレイヤーの座標処理とマス塗りの判定
     this.players.forEach((player) => {
diff --git a/apps/server/src/network/handlers/game/createGameOutputAdapter.ts b/apps/server/src/network/handlers/game/createGameOutputAdapter.ts
index 4e43e44..58310c4 100644
--- a/apps/server/src/network/handlers/game/createGameOutputAdapter.ts
+++ b/apps/server/src/network/handlers/game/createGameOutputAdapter.ts
@@ -4,7 +4,7 @@
  */
 import { Server } from "socket.io";
 import { protocol } from "@repo/shared";
-import type { gridMapTypes, playerTypes, roomTypes } from "@repo/shared";
+import type { gridMapTypes, playerTypes, roomTypes, UpdatePlayersPayload } from "@repo/shared";
 import type { GameOutputPort } from "@server/domains/game/application/ports/gameUseCasePorts";
 import { createEmitToRoom } from "@server/network/adapters/socketEmitters";
 import type { CommonHandlerContext } from "../CommonHandler";
@@ -14,7 +14,6 @@
 type PongPayload = { clientTime: number; serverTime: number };
 type GameStartPayload = { startTime: number };
 type CurrentPlayersPayload = playerTypes.PlayerData[];
-type UpdatePlayersPayload = playerTypes.PlayerData[];
 type MapCellUpdatesPayload = gridMapTypes.CellUpdate[];
 
 /** ゲーム出力アダプターのインターフェース */
diff --git a/packages/shared/src/domains/game/game.type.ts b/packages/shared/src/domains/game/game.type.ts
new file mode 100644
index 0000000..ed51d9f
--- /dev/null
+++ b/packages/shared/src/domains/game/game.type.ts
@@ -0,0 +1,12 @@
+/**
+ * game.type
+ * ゲーム進行で利用する共有型を定義する
+ */
+import type { CellUpdate } from "../gridMap/gridMap.type";
+import type { PlayerData } from "../player/player.type";
+
+/** 1ティック分のプレイヤー差分更新とマップ差分を表す共有データ */
+export interface TickData {
+  playerUpdates: PlayerData[];
+  cellUpdates: CellUpdate[];
+}
diff --git a/packages/shared/src/index.ts b/packages/shared/src/index.ts
index 266bcd1..48c6e17 100644
--- a/packages/shared/src/index.ts
+++ b/packages/shared/src/index.ts
@@ -2,9 +2,11 @@
 export * as gridMapTypes from "./domains/gridMap/gridMap.type";
 export * as gridMapLogic from "./domains/gridMap/gridMap.logic";
 export * as playerTypes from "./domains/player/player.type";
+export * as gameTypes from "./domains/game/game.type";
 export * as appTypes from "./domains/app/app.type";
 export * as appConsts from "./domains/app/app.const";
 export * as roomTypes from "./domains/room/room.type";
 export * as roomConsts from "./domains/room/room.const";
 export * as protocol from "./protocol/events";
+export type { UpdatePlayersPayload } from "./protocol/events";
 export * as config from "./config";
\ No newline at end of file
diff --git a/packages/shared/src/protocol/events.ts b/packages/shared/src/protocol/events.ts
index 6082e05..28a710f 100644
--- a/packages/shared/src/protocol/events.ts
+++ b/packages/shared/src/protocol/events.ts
@@ -3,6 +3,8 @@
  * ソケット通信で利用するイベント名定数を定義する
  * クライアントとサーバー間のイベント契約を共有する
  */
+import type { TickData } from "../domains/game/game.type";
+
 /** ソケットイベント名の一覧定数 */
 export const SocketEvents = {
   // 接続・切断イベント名
@@ -31,3 +33,6 @@
   PONG: "pong",           // サーバーからの現在時刻レスポンス
   GAME_END: "game-end",   // 3分経過時のゲーム終了通知
 } as const;
+
+/** UPDATE_PLAYERS イベントで送受信するプレイヤー差分配列 */
+export type UpdatePlayersPayload = TickData["playerUpdates"];