diff --git a/ChangeLog b/ChangeLog
index 909706d304..3ae7dfaf97 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Thu Apr  1 11:36:04 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* io.c (rb_io_initialize): fixed a rdoc miss that textmode and
+	  bimode flag explanation was reversed each other.  a patch from
+	  Heesob Park in [ruby-core:29166].
+
 Thu Apr  1 09:54:27 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* include/ruby/ruby.h (RUBY_{DEFAULT,NEVER}_FREE): added.
diff --git a/io.c b/io.c
index 031a92bf82..362beb192b 100644
--- a/io.c
+++ b/io.c
@@ -6316,9 +6316,9 @@ rb_io_stdio_file(rb_io_t *fptr)
  *  :encoding ::
  *    specifies external and internal encodings as "extern:intern".
  *  :textmode ::
- *    If the value is truth value, same as "b" in argument <code>mode</code>.
- *  :binmode ::
  *    If the value is truth value, same as "t" in argument <code>mode</code>.
+ *  :binmode ::
+ *    If the value is truth value, same as "b" in argument <code>mode</code>.
  *  :autoclose ::
  *    If the value is +false+, the _fd_ will be kept open after this
  *    +IO+ instance gets finalized.