diff --git a/app/services/user_service.py b/app/services/user_service.py
new file mode 100644
index 0000000..3aff93c
--- /dev/null
+++ b/app/services/user_service.py
@@ -0,0 +1,15 @@
+# ログイン処理書きかけ
+from app.models.workout import User
+from app.repositories.workout_repository import WorkoutRepository
+
+class UserService:
+    def __init__(self):
+        # self.users = []
+        self.workout_repository = WorkoutRepository()
+
+    def login(self, username: str, password: str) -> User:
+        # TODO:入力されたパスワードをハッシュ化して比較する処理を追加する
+        for user in self.users:
+            if user.username == username and user.password == password:
+                return user
+        return None
\ No newline at end of file