diff --git a/ChangeLog b/ChangeLog
index 892ccb3674..83bd015cdb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sat Sep  6 19:36:34 2008  Tanaka Akira  <akr@fsij.org>
+
+	* io.c (rb_io_binmode): clear newline flags in writeconv_pre_ecflags.
+
 Sat Sep  6 18:47:40 2008  Tanaka Akira  <akr@fsij.org>
 
 	* transcode.c (str_transcode0): check ECONV_HTML_TEXT_ENCODER and
diff --git a/io.c b/io.c
index 1833835cc9..88217efe0a 100644
--- a/io.c
+++ b/io.c
@@ -3500,6 +3500,7 @@ rb_io_binmode(VALUE io)
         rb_econv_binmode(fptr->writeconv);
     fptr->mode |= FMODE_BINMODE;
     fptr->mode &= ~FMODE_TEXTMODE;
+    fptr->writeconv_pre_ecflags &= ~(ECONV_UNIVERSAL_NEWLINE_DECODER|ECONV_CRLF_NEWLINE_ENCODER|ECONV_CR_NEWLINE_ENCODER);
     return io;
 }