diff --git a/app/controllers/admin/ng_words_controller.rb b/app/controllers/admin/ng_words_controller.rb
index 1af50acb42..e26ca96b8c 100644
--- a/app/controllers/admin/ng_words_controller.rb
+++ b/app/controllers/admin/ng_words_controller.rb
@@ -11,18 +11,31 @@ module Admin
     def create
       authorize :ng_words, :create?
 
+      begin
+        test_words
+      rescue
+        flash[:alert] = I18n.t('admin.ng_words.test_error')
+        redirect_to after_update_redirect_path
+        return
+      end
+
       @admin_settings = Form::AdminSettings.new(settings_params)
 
       if @admin_settings.save
         flash[:notice] = I18n.t('generic.changes_saved_msg')
         redirect_to after_update_redirect_path
       else
-        render :index
+        render :show
       end
     end
 
     private
 
+    def test_words
+      ng_words = settings_params['ng_words'].split(/\r\n|\r|\n/)
+      Admin::NgWord.reject_with_custom_words?('Sample text', ng_words)
+    end
+
     def after_update_redirect_path
       admin_ng_words_path
     end
diff --git a/app/models/admin/ng_word.rb b/app/models/admin/ng_word.rb
index 42c84b0f8e..b99c52a714 100644
--- a/app/models/admin/ng_word.rb
+++ b/app/models/admin/ng_word.rb
@@ -3,7 +3,11 @@
 class Admin::NgWord
   class << self
     def reject?(text)
-      ng_words.any? { |word| text.include?(word) }
+      ng_words.any? { |word| include?(text, word) }
+    end
+
+    def reject_with_custom_words?(text, custom_ng_words)
+      custom_ng_words.any? { |word| include?(text, word) }
     end
 
     def hashtag_reject?(hashtag_count)
@@ -16,6 +20,14 @@ class Admin::NgWord
 
     private
 
+    def include?(text, word)
+      if word.start_with?('?') && word.size >= 2
+        text =~ /#{word[1..]}/i
+      else
+        text.include?(word)
+      end
+    end
+
     def ng_words
       Setting.ng_words || []
     end
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 5ee09dadbf..e89c236b0f 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -600,6 +600,7 @@ en:
       hide_local_users_for_anonymous: Hide timeline local user posts from anonymous
       keywords: Reject keywords
       post_hash_tags_max: Hash tags max for posts
+      test_error: Testing is returned any errors
       title: NG words and against spams
     relationships:
       title: "%{acct}'s relationships"
diff --git a/config/locales/ja.yml b/config/locales/ja.yml
index 1690c7f3dd..d27e475cb6 100644
--- a/config/locales/ja.yml
+++ b/config/locales/ja.yml
@@ -599,6 +599,7 @@ ja:
       hide_local_users_for_anonymous: ログインしていない状態でローカルユーザーの投稿をタイムラインから取得できないようにする
       keywords: 投稿できないキーワード
       post_hash_tags_max: 投稿に設定可能なハッシュタグの最大数
+      test_error: NGワードのテストに失敗しました。正規表現のミスが含まれているかもしれません
       title: NGワードとスパム
     relationships:
       title: "%{acct} さんのフォロー・フォロワー"