diff --git a/app/views/common/_diff.html.erb b/app/views/common/_diff.html.erb
index 3e03720f8..cf99967f7 100644
--- a/app/views/common/_diff.html.erb
+++ b/app/views/common/_diff.html.erb
@@ -23,11 +23,11 @@
 <tr>
   <th class="line-num"><%= line.nb_line_left %></th>
   <td class="line-code <%= line.type_diff_left %>">
-    <pre><%= Redmine::CodesetUtil.to_utf8_by_setting(line.html_line_left) %></pre>
+    <pre><%= Redmine::CodesetUtil.to_utf8_by_setting(line.html_line_left).html_safe %></pre>
   </td>
   <th class="line-num"><%= line.nb_line_right %></th>
   <td class="line-code <%= line.type_diff_right %>">
-    <pre><%= Redmine::CodesetUtil.to_utf8_by_setting(line.html_line_right) %></pre>
+    <pre><%= Redmine::CodesetUtil.to_utf8_by_setting(line.html_line_right).html_safe %></pre>
   </td>
 </tr>
 <% end -%>
@@ -54,7 +54,7 @@
   <th class="line-num"><%= line.nb_line_left %></th>
   <th class="line-num"><%= line.nb_line_right %></th>
   <td class="line-code <%= line.type_diff %>">
-    <pre><%= Redmine::CodesetUtil.to_utf8_by_setting(line.html_line) %></pre>
+    <pre><%= Redmine::CodesetUtil.to_utf8_by_setting(line.html_line).html_safe %></pre>
   </td>
 </tr>
 <% end -%>