diff --git a/ChangeLog b/ChangeLog
index 8038add8d7a651..c57122a27cb2e6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Jan 24 11:43:47 2013  Narihiro Nakamura  <authornari@gmail.com>
+
+	* eval.c (f_current_dirname): Add documentation about "__dir__
+	  returns always an absolute path". [Bug #7729]
+
 Thu Jan 24 10:28:30 2013  Eric Hodel  <drbrain@segment7.net>
 
 	* NEWS (RDoc):  Added mention of page support and markdown support.
diff --git a/eval.c b/eval.c
index 1b746f26ad9fc8..13602bc66337d1 100644
--- a/eval.c
+++ b/eval.c
@@ -1507,6 +1507,7 @@ rb_f_callee_name(void)
  *
  *  Returns the value of <code>File.dirname(__FILE__)</code>
  *  If <code>__FILE__</code> is <code>nil</code>, it returns <code>nil</code>.
+ *  And it returns always an absolute path.
  *
  */
 static VALUE