diff --git a/app/controllers/fluentd/settings_controller.rb b/app/controllers/fluentd/settings_controller.rb
index 72b2eb7..dd45c9f 100644
--- a/app/controllers/fluentd/settings_controller.rb
+++ b/app/controllers/fluentd/settings_controller.rb
@@ -34,6 +34,9 @@ class Fluentd::SettingsController < ApplicationController
     if params[:back]
       return render :in_tail_after_file_choose
     end
+    unless @setting.valid?
+      return render :in_tail_after_format
+    end
   end
 
   def in_tail_finish