diff --git a/ChangeLog b/ChangeLog
index d83a0f137a..d71b42b976 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Mon Nov 16 01:58:08 2009  Yusuke Endoh  <mame@tsg.ne.jp>
+
+	* include/ruby/ruby.h (rb_classext_t): annotate @internal.
+
 Mon Nov 16 01:35:34 2009  Tanaka Akira  <akr@fsij.org>
 
 	* encoding.c (rb_filesystem_encindex): use default external encoding
diff --git a/include/ruby/ruby.h b/include/ruby/ruby.h
index 84bce04c07..97ad41c70b 100644
--- a/include/ruby/ruby.h
+++ b/include/ruby/ruby.h
@@ -564,6 +564,7 @@ struct RObject {
      RCLASS_IV_INDEX_TBL(rb_obj_class(o)) : \
      ROBJECT(o)->as.heap.iv_index_tbl)
 
+/** @internal */
 typedef struct {
     VALUE super;
     struct st_table *iv_tbl;