diff --git a/ChangeLog b/ChangeLog
index 6b09fe7ee9..07c8eb625c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Mar  3 23:41:42 2015  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* tool/redmine-backporter.rb (Readline.readline): drop untreated control
+	  characters.
+
 Tue Mar  3 22:25:24 2015  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* test/lib/envutil.rb (EnvUtil.invoke_ruby): need to rescue because
diff --git a/tool/redmine-backporter.rb b/tool/redmine-backporter.rb
index 54cb631543..0bd0b3f898 100755
--- a/tool/redmine-backporter.rb
+++ b/tool/redmine-backporter.rb
@@ -239,8 +239,10 @@ class << Readline
         print cls
         print line
       else
-        print c
-        line << c
+        if c >= " "
+          print c
+          line << c
+        end
       end
     end
   end