diff --git a/app/src/main/java/com/example/sprout/refactor/repository/RegistrationRepository.java b/app/src/main/java/com/example/sprout/refactor/repository/RegistrationRepository.java
index 0f41a14..16ae86f 100644
--- a/app/src/main/java/com/example/sprout/refactor/repository/RegistrationRepository.java
+++ b/app/src/main/java/com/example/sprout/refactor/repository/RegistrationRepository.java
@@ -20,6 +20,7 @@
 
     private RegistrationService registrationService = null;
     private Subject<Account> registrationSubject = PublishSubject.<Account>create().toSerialized();
+    private Subject<Throwable> registrationErrorSubject = PublishSubject.<Throwable>create().toSerialized();
 
     public RegistrationRepository() {
         this.registrationService = new Retrofit
@@ -46,12 +47,16 @@
                             registrationSubject.onNext(account);
                         },
                         error -> {
-                            System.out.println("error");
-                            // TODO:error handling
+                            System.out.println("hogehoge");
+                            registrationErrorSubject.onNext(error);
                         });
     }
 
     public Observable<Account> getRegistrationObservable() {
         return registrationSubject.hide();
     }
+
+    public Observable<Throwable> getRegistrationErrorObservable() {
+        return registrationErrorSubject.hide();
+    }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/example/sprout/refactor/viewmodel/RegistrationViewModel.java b/app/src/main/java/com/example/sprout/refactor/viewmodel/RegistrationViewModel.java
index c4ddc8d..bcfbe0a 100644
--- a/app/src/main/java/com/example/sprout/refactor/viewmodel/RegistrationViewModel.java
+++ b/app/src/main/java/com/example/sprout/refactor/viewmodel/RegistrationViewModel.java
@@ -54,14 +54,20 @@
                 registrationRepository.getRegistrationObservable()
                         .observeOn(AndroidSchedulers.mainThread())
                         .subscribe(account -> {
-                            ModelLocator.getModel(ModelLocator.Tag.ACCOUNT, Account.class).setAccount(account);
-                            preferenceUtil.saveInt(PreferenceUtil.Key.USER_ID, account.getUserID());
-                            preferenceUtil.saveBoolean(PreferenceUtil.Key.REGISTERED, true);
-                            toastMessanger.showToast(new ToastMessage(Sprout.get().getResources().getString(R.string.success_registration), ToastMessage.Length.LONG));
-                            navigationMessenger.navigateTo(new NavigationMessage(NavigationMessage.Type.Start, RoomListActivity.class));
-                            navigationMessenger.navigateTo(new NavigationMessage(NavigationMessage.Type.Finsih));
-                        }, error -> {
-                            toastMessanger.showToast(new ToastMessage(Sprout.get().getResources().getString(R.string.fail_registration), ToastMessage.Length.SHORT));
+                                    ModelLocator.getModel(ModelLocator.Tag.ACCOUNT, Account.class).setAccount(account);
+                                    preferenceUtil.saveInt(PreferenceUtil.Key.USER_ID, account.getUserID());
+                                    preferenceUtil.saveBoolean(PreferenceUtil.Key.REGISTERED, true);
+                                    toastMessanger.showToast(new ToastMessage(Sprout.get().getResources().getString(R.string.success_registration), ToastMessage.Length.LONG));
+                                    navigationMessenger.navigateTo(new NavigationMessage(NavigationMessage.Type.Start, RoomListActivity.class));
+                                    navigationMessenger.navigateTo(new NavigationMessage(NavigationMessage.Type.Finsih));
+                                }
+                        ))
+        ;
+        subscriptions.add(
+                registrationRepository.getRegistrationErrorObservable()
+                        .observeOn(AndroidSchedulers.mainThread())
+                        .subscribe(error -> {
+                            toastMessanger.showToast(new ToastMessage(Sprout.get().getResources().getString(R.string.fail_registration), ToastMessage.Length.LONG));
                         })
         );
     }