diff --git a/src/main/java/com/example/springtest/demo/resources/UserRest.java b/src/main/java/com/example/springtest/demo/resources/UserRest.java
index e5ea139..3f9ad5c 100644
--- a/src/main/java/com/example/springtest/demo/resources/UserRest.java
+++ b/src/main/java/com/example/springtest/demo/resources/UserRest.java
@@ -14,7 +14,7 @@
 @Path("/users")
 public class UserRest {
 
-    private Map<String, User> users = new HashMap<>();
+//    private Map<String, User> users = new HashMap<>();
 
     @Autowired // This means to get the bean called userRepository
     // Which is auto-generated by Spring, we will use it to handle the data
@@ -57,7 +57,7 @@
     public User createUser(@FormParam("name") String name, @FormParam("password") String password) {
         String uId = UUID.randomUUID().toString();
         User user = new User(uId, name, password);
-        users.put(uId, user);
+//        users.put(uId, user);
         return userRepository.save(user);
     }
 
@@ -65,11 +65,12 @@
     @PUT
     @Produces(MediaType.APPLICATION_JSON)
     public User updateUser(@PathParam("uId") String uId, @Nullable @FormParam("name") String name, @Nullable @FormParam("password") String password) {
-        User user = users.get(uId);
-        if (user != null) {
-            user.setName(name);
-            user.setPassword(password);
-            return userRepository.save(user);    // JSONが返る
+//        User user = users.get(uId);
+        Optional<User> user = userRepository.findById(uId);
+        if (user.isPresent()) {
+            user.get().setName(name);
+            user.get().setPassword(password);
+            return userRepository.save(user.get());    // JSONが返る
         } else { // uIdが無ければ
             throw new WebApplicationException(404);    // 404が返る
         }
@@ -79,10 +80,10 @@
     @DELETE
     @Produces(MediaType.APPLICATION_JSON)
     public User deleteUser(@PathParam("uId") String uId) {
-        User user = users.remove(uId);
-        if (user != null) {
+        Optional<User> user = userRepository.findById(uId);
+        if (user.isPresent()) {
             userRepository.deleteById(uId);
-            return user;    // JSONが返る
+            return user.get();   // JSONが返る
         } else { // uIdが無ければ
             throw new WebApplicationException(410);    // 410が返る(GONE)
         }