diff --git a/app/src/main/java/org/ntlab/amaryllis/client/LoginActivity.java b/app/src/main/java/org/ntlab/amaryllis/client/LoginActivity.java
index 8b210d4..8fe1519 100644
--- a/app/src/main/java/org/ntlab/amaryllis/client/LoginActivity.java
+++ b/app/src/main/java/org/ntlab/amaryllis/client/LoginActivity.java
@@ -10,6 +10,7 @@
 import android.widget.Button;
 import android.widget.EditText;
 import android.widget.TextView;
+import android.widget.Toast;
 
 import org.ntlab.amaryllis.client.entities.SignUpJson;
 import org.ntlab.amaryllis.client.resources.AccountsRest;
@@ -50,15 +51,20 @@
                 call.enqueue(new Callback<SignUpJson>(){
                     @Override
                     public void onResponse(Call<SignUpJson> call, Response<SignUpJson> response) {
-                        SignUpJson signUpJson =response.body();
-                        Amaryllis app = (Amaryllis) getApplication();
-                        app.setToken(signUpJson.getToken());
-                        app.setUid(nameText.getText().toString());
-                        app.setPassword(passWordEditText.getText().toString());
-                        app.setName(nameText.getText().toString());
-                        Intent intent = new Intent(getApplication(), MainActivity.class);
-                        startActivity(intent);
-                        finish();
+                        if (response.isSuccessful()) {
+                            SignUpJson signUpJson =response.body();
+                            Amaryllis app = (Amaryllis) getApplication();
+                            app.setToken(signUpJson.getToken());
+                            app.setUid(nameText.getText().toString());
+                            app.setPassword(passWordEditText.getText().toString());
+                            app.setName(nameText.getText().toString());
+                            Intent intent = new Intent(getApplication(), MainActivity.class);
+                            startActivity(intent);
+                            finish();
+                        }else {
+                            Toast.makeText(LoginActivity.this,
+                                    "nameもしくはパスワードが違います", Toast.LENGTH_SHORT).show();
+                        }
                     }
 
                     @Override
diff --git a/app/src/main/java/org/ntlab/amaryllis/client/SignUpActivity.java b/app/src/main/java/org/ntlab/amaryllis/client/SignUpActivity.java
index 4894894..ba4cf1c 100644
--- a/app/src/main/java/org/ntlab/amaryllis/client/SignUpActivity.java
+++ b/app/src/main/java/org/ntlab/amaryllis/client/SignUpActivity.java
@@ -13,6 +13,7 @@
 import android.widget.Button;
 import android.widget.EditText;
 import android.widget.TextView;
+import android.widget.Toast;
 
 import org.ntlab.amaryllis.client.entities.LoginJson;
 import org.ntlab.amaryllis.client.entities.SignUpJson;
@@ -71,16 +72,21 @@
                 call.enqueue(new Callback<SignUpJson>(){
                     @Override
                     public void onResponse(Call<SignUpJson> call, Response<SignUpJson> response) {
-                        SignUpJson signUpJson =response.body();
-                        String token = signUpJson.getToken();
-                        Amaryllis amaryllis = (Amaryllis) getApplication();
-                        amaryllis.setToken(token);
-                        amaryllis.setUid(signUpJson.getUid());
-                        amaryllis.setPassword(passWordEditText.getText().toString());
-                        amaryllis.setName(nameEditText.getText().toString());
-                        Intent intent = new Intent(getApplication(), MainActivity.class);
-                        startActivity(intent);
-                        finish();
+                        if (response.isSuccessful()) {
+                            SignUpJson signUpJson = response.body();
+                            String token = signUpJson.getToken();
+                            Amaryllis amaryllis = (Amaryllis) getApplication();
+                            amaryllis.setToken(token);
+                            amaryllis.setUid(signUpJson.getUid());
+                            amaryllis.setPassword(passWordEditText.getText().toString());
+                            amaryllis.setName(nameEditText.getText().toString());
+                            Intent intent = new Intent(getApplication(), MainActivity.class);
+                            startActivity(intent);
+                            finish();
+                        }else {
+                            Toast.makeText(SignUpActivity.this,
+                                    "既にその名前のアカウントが存在します。", Toast.LENGTH_SHORT).show();
+                        }
                     }
 
                     @Override
diff --git a/app/src/main/res/layout/fragment_account.xml b/app/src/main/res/layout/fragment_account.xml
index b295566..8028c4e 100644
--- a/app/src/main/res/layout/fragment_account.xml
+++ b/app/src/main/res/layout/fragment_account.xml
@@ -25,8 +25,8 @@
 
     <EditText
         android:id="@+id/name"
-        android:layout_width="177dp"
-        android:layout_height="37dp"
+        android:layout_width="196dp"
+        android:layout_height="52dp"
         android:ems="10"
         android:gravity="left"
         android:inputType="textPersonName"