diff --git a/app/controllers/user_sessions_controller.rb b/app/controllers/user_sessions_controller.rb
index 816d593..8c943ee 100644
--- a/app/controllers/user_sessions_controller.rb
+++ b/app/controllers/user_sessions_controller.rb
@@ -11,4 +11,8 @@ def destroy
     reset_session
     redirect_to root_path, notice: 'ログアウトしました'
   end
+
+  def failure
+    redirect_to root_path, notice: 'ログインをキャンセルしました'
+  end
 end
diff --git a/config/initializers/omniauth.rb b/config/initializers/omniauth.rb
index 6de5227..084d564 100644
--- a/config/initializers/omniauth.rb
+++ b/config/initializers/omniauth.rb
@@ -1,5 +1,9 @@
-  Rails.application.config.middleware.use OmniAuth::Builder do
-    provider :github,
-      Rails.application.credentials.github[:client_id],
-      Rails.application.credentials.github[:client_secret]
-  end
+Rails.application.config.middleware.use OmniAuth::Builder do
+  provider :github,
+    Rails.application.credentials.github[:client_id],
+    Rails.application.credentials.github[:client_secret]
+
+  OmniAuth.config.on_failure = Proc.new { |env|
+    OmniAuth::FailureEndpoint.new(env).redirect_to_failure
+  }
+end
diff --git a/config/routes.rb b/config/routes.rb
index d14a46c..ba18eb2 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -9,5 +9,6 @@
   # Defines the root path route ("/")
   root "groups#index"
   get "auth/:provider/callback" => "user_sessions#create"
+  get "auth/failure" => "user_sessions#failure"
   delete "/logout" => "user_sessions#destroy"
 end
diff --git a/spec/requests/user_sessions_spec.rb b/spec/requests/user_sessions_spec.rb
index 5534fd7..6452be3 100644
--- a/spec/requests/user_sessions_spec.rb
+++ b/spec/requests/user_sessions_spec.rb
@@ -57,4 +57,11 @@
       expect(response).to redirect_to(root_path)
     end
   end
+
+  describe 'GET /failure' do
+    it 'redirects to root_path' do
+      get '/auth/failure'
+      expect(response).to redirect_to(root_path)
+    end
+  end
 end
diff --git a/spec/system/users_spec.rb b/spec/system/users_spec.rb
index e6f82ba..2669535 100644
--- a/spec/system/users_spec.rb
+++ b/spec/system/users_spec.rb
@@ -4,34 +4,57 @@
 
 RSpec.describe 'Users', type: :system do
   describe 'user authentication' do
-    it 'allows users to login' do
-      visit root_path
-      expect(page).to have_content 'GitHubアカウントが必要です'
+    context 'when authentication is successful' do
+      it 'allows users to login' do
+        visit root_path
+        expect(page).to have_content 'GitHubアカウントが必要です'
+
+        expect do
+          click_button 'サインアップ / ログインをして2次会グループを作成'
+
+          expect(page).to have_content 'ログインしました'
+        end.to change(User, :count).by(1)
+
+        expect(page).to have_current_path(new_group_path)
+      end
+    end
+
+    context 'when user logs out' do
+      it 'allows users to logout' do
+        visit root_path
+        expect(page).to have_content 'GitHubアカウントが必要です'
+        expect(page).not_to have_content 'ログアウト'
 
-      expect do
         click_button 'サインアップ / ログインをして2次会グループを作成'
+        expect(page).to have_current_path(new_group_path)
 
-        expect(page).to have_content 'ログインしました'
-      end.to change(User, :count).by(1)
+        click_link 'キャンセル'
+        expect(page).to have_current_path(groups_path)
+        expect(page).not_to have_content 'GitHubアカウントが必要です'
 
-      expect(page).to have_current_path(new_group_path)
+        click_button 'ログアウト'
+        expect(page).to have_content 'ログアウトしました'
+        expect(page).to have_content 'GitHubアカウントが必要です'
+      end
     end
 
-    it 'allows users to logout' do
-      visit root_path
-      expect(page).to have_content 'GitHubアカウントが必要です'
-      expect(page).not_to have_content 'ログアウト'
+    context 'when authentication is failed' do
+      before do
+        OmniAuth.config.mock_auth[:github] = :invalid_credentials
+      end
+
+      it 'redirects to root_path' do
+        visit root_path
+        expect(page).to have_content 'GitHubアカウントが必要です'
 
-      click_button 'サインアップ / ログインをして2次会グループを作成'
-      expect(page).to have_current_path(new_group_path)
+        expect do
+          click_button 'サインアップ / ログインをして2次会グループを作成'
 
-      click_link 'キャンセル'
-      expect(page).to have_current_path(groups_path)
-      expect(page).not_to have_content 'GitHubアカウントが必要です'
+          expect(page).to have_content 'ログインをキャンセルしました'
+        end.not_to change(User, :count)
 
-      click_button 'ログアウト'
-      expect(page).to have_content 'ログアウトしました'
-      expect(page).to have_content 'GitHubアカウントが必要です'
+        expect(page).to have_current_path(root_path)
+      end
     end
   end
 end