diff --git a/ChangeLog b/ChangeLog
index a731c64a5c..18fb8dd84b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Apr 22 20:51:58 2008  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* ext/nkf/nkf-utf8/nkf.c (z_conv): characters must be nkf_char.
+
 Tue Apr 22 19:23:05 2008  Akinori MUSHA  <knu@iDaemons.org>
 
 	* enumerator.c (enumerator_initialize): Remove an undocumented
diff --git a/ext/nkf/nkf-utf8/nkf.c b/ext/nkf/nkf-utf8/nkf.c
index a711938df4..084b2c469f 100644
--- a/ext/nkf/nkf-utf8/nkf.c
+++ b/ext/nkf/nkf-utf8/nkf.c
@@ -3390,7 +3390,7 @@ void z_conv(nkf_char c2, nkf_char c1)
     if (alpha_f & 16) {
 	/* JIS X 0208 Katakana to JIS X 0201 Katakana */
 	if (c2 == 0x21) {
-	    char c = 0;
+	    nkf_char c = 0;
 	    switch (c1) {
 	    case 0x23:
 		/* U+3002 (0x8142) Ideographic Full Stop -> U+FF61 (0xA1) Halfwidth Ideographic Full Stop */