diff --git a/ChangeLog b/ChangeLog
index db62391a05..e92f608bc6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sat Jan 23 23:12:56 2010  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* lib/rdoc/generator/html.rb (RDoc::Generator::HTML#gen_into):
+	  make the rdoc(generating html) run faster and use less memory.
+	  patch by Tetsu Soh [ruby-core:27656]
+
 Sat Jan 23 19:54:48 2010  Masaki Suketa <masaki.suketa@nifty.ne.jp>
 
 	* ext/win32ole/win32ole.c: add WIN32OLE.ole_initialize,
diff --git a/lib/rdoc/generator/html.rb b/lib/rdoc/generator/html.rb
index 60e0c175fe..3bce7b21aa 100644
--- a/lib/rdoc/generator/html.rb
+++ b/lib/rdoc/generator/html.rb
@@ -231,6 +231,10 @@ class RDoc::Generator::HTML
       open op_file, 'w' do |io|
         item.write_on io, file_list, class_list, method_list
       end
+
+      file_list.clear
+      class_list.clear
+      method_list.clear
     end
   end