diff --git a/app/controllers/admin/announcements_controller.rb b/app/controllers/admin/announcements_controller.rb
index a9b8fd5..f7e5d6f 100644
--- a/app/controllers/admin/announcements_controller.rb
+++ b/app/controllers/admin/announcements_controller.rb
@@ -472,7 +472,7 @@ class Admin::AnnouncementsController < OrbitAdminController
       end
     end
     if request.xhr?
-      render :nothing => true, :status => 204
+      render :body => nil, :status => 204
     else
       redirect_to admin_announcements_path
     end
diff --git a/app/views/announcements/index.html.erb b/app/views/announcements/index.html.erb
index a7c063c..41282cd 100644
--- a/app/views/announcements/index.html.erb
+++ b/app/views/announcements/index.html.erb
@@ -2,7 +2,6 @@
 <% @params = @index_controller.instance_variable_get(:@params) rescue {}
    @enable_search_flag = @index_controller.instance_variable_get(:@enable_search_flag) rescue false
 %>
-
 <% if @enable_search_flag %>
   <style type="text/css">
     #category_select_box{
@@ -65,7 +64,7 @@
           <input class="search_box" type="text" name="etime" value="<%= @params['etime'].to_s.gsub(/\"/,'') %>" placeholder="<%= t('announcement.etime') %>" data-format="yyyy/mm/dd">
         </div>
       </div>
-      <input type="hidden" name="authenticity_token" value="<%= (0...46).map { ('a'..'z').to_a[rand(26)] }.join %>">
+      <input type="hidden" name="authenticity_token" value="<%= form_authenticity_token %>">
       <input class="search_box" type="submit" value="<%= t('announcement.search') %>">
     </div>
   </form>