diff --git a/ChangeLog b/ChangeLog
index 410abc00d0..1ab0d894d6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Wed Nov  6 19:30:44 2013  Masaya Tarui  <tarui@ruby-lang.org>
+
+	* common.mk (help): add texts about gcbench.
+
 Wed Nov  6 16:32:32 2013  Martin Duerst <duerst@it.aoyama.ac.jp>
 
 	* lib/open3.rb: tweaked grammar in comments
diff --git a/common.mk b/common.mk
index ac0413211f..f8ab233d69 100644
--- a/common.mk
+++ b/common.mk
@@ -1088,6 +1088,8 @@ help: PHONY
 	"  test-rubyspec:   run RubySpec test suite" \
 	"  update-rubyspec: update local copy of RubySpec" \
 	"  benchmark:       benchmark this ruby and COMPARE_RUBY" \
+	"  gcbench:         gc benchmark [GCBENCH_ITEM=<item_name>]" \
+	"  gcbench-rdoc:    gc benchmark with GCBENCH_ITEM=rdoc" \
 	"  install:         install all ruby distributions" \
 	"  install-nodoc:   install without rdoc" \
 	"  install-cross:   install cross compiling staff" \