diff --git a/src/main.ts b/src/main.ts
index aa7fa3b..e6e86c2 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -10,7 +10,7 @@ import { StoneCreator } from './model/stone';
     const board = new Board();
     const io = new IO(prompt);
 
-    const othello = new Othello(board, StoneCreator, PlayerCreator, io);
+    const othello = new Othello(board, new StoneCreator, new PlayerCreator, io);
     othello.init();
   } catch (e) {
     const _e = e as Error;
diff --git a/src/model/othello.ts b/src/model/othello.ts
index db2a114..51ed9d5 100644
--- a/src/model/othello.ts
+++ b/src/model/othello.ts
@@ -23,7 +23,7 @@ export const directions: XYDirection[] = [
 
 export class Othello {
   private readonly board: IBoard;
-  private readonly StoneCreator: IStoneCreator;
+  private readonly stoneCreator: IStoneCreator;
   private readonly player1: IPlayer;
   private readonly player2: IPlayer;
   private readonly io: IIO;
@@ -31,11 +31,11 @@ export class Othello {
   private pass = 0;
   private countStone = 0;
 
-  constructor(board: IBoard, StoneCreator: IStoneCreator, PlayerCreator: IPlayerCreator, io: IIO) {
+  constructor(board: IBoard, stoneCreator: IStoneCreator, playerCreator: IPlayerCreator, io: IIO) {
     this.board = board;
-    this.StoneCreator = StoneCreator;
-    this.player1 = PlayerCreator.factory('black', '黒');
-    this.player2 = PlayerCreator.factory('white', '白');
+    this.stoneCreator = stoneCreator;
+    this.player1 = playerCreator.factory('black', '黒');
+    this.player2 = playerCreator.factory('white', '白');
     this.io = io;
 
     this.turnPlayer = this.player1;
@@ -51,9 +51,9 @@ export class Othello {
       for (let y = 0; y < 2; y++) {
         for (let x = 0; x < 2; x++) {
           if (x === y) {
-            this.board.putStone({ y: y + base, x: x + base }, this.StoneCreator.factory('black'));
+            this.board.putStone({ y: y + base, x: x + base }, this.stoneCreator.factory('black'));
           } else {
-            this.board.putStone({ y: y + base, x: x + base }, this.StoneCreator.factory('white'));
+            this.board.putStone({ y: y + base, x: x + base }, this.stoneCreator.factory('white'));
           }
         }
       }
@@ -79,7 +79,7 @@ export class Othello {
       throw new Error('ひっくり返せる石がないよ');
     }
 
-    this.board.putStone(coodinate, this.StoneCreator.factory(this.turnPlayer.color));
+    this.board.putStone(coodinate, this.stoneCreator.factory(this.turnPlayer.color));
     flipableStones.forEach(flipableStone => {
       const stone = this.board.getStone(flipableStone);
       stone?.flip();
diff --git a/src/model/player.ts b/src/model/player.ts
index 8201d20..e82677a 100644
--- a/src/model/player.ts
+++ b/src/model/player.ts
@@ -19,8 +19,8 @@ export interface IPlayerCreator {
   factory: (color: StoneState, name: string) => IPlayer
 }
 
-export const PlayerCreator: IPlayerCreator = class PlayerCreator {
-  public static factory = (color: StoneState, name: string) => {
+export class PlayerCreator implements IPlayerCreator {
+  public factory = (color: StoneState, name: string) => {
     return new Player(color, name);
   }
 }
diff --git a/src/model/stone.ts b/src/model/stone.ts
index 7ac992c..0f827bd 100644
--- a/src/model/stone.ts
+++ b/src/model/stone.ts
@@ -29,8 +29,8 @@ export interface IStoneCreator {
   factory: (value: StoneState) => IStone;
 }
 
-export const StoneCreator: IStoneCreator = class StoneCreator {
-  public static factory = (value: StoneState) => {
+export class StoneCreator implements IStoneCreator {
+  public factory = (value: StoneState) => {
     return new Stone(value);
   };
 };