diff --git a/ext/mbstring/libmbfl/filters/mbfilter_sjis_2004.c b/ext/mbstring/libmbfl/filters/mbfilter_sjis_2004.c
index 4f09af3b736..0f369b56bd8 100644
--- a/ext/mbstring/libmbfl/filters/mbfilter_sjis_2004.c
+++ b/ext/mbstring/libmbfl/filters/mbfilter_sjis_2004.c
@@ -633,6 +633,8 @@ retry:
 			if (filter->to->no_encoding == mbfl_no_encoding_eucjp2004) {
 				CK((*filter->output_function)(0x8e, filter->data));
 				CK((*filter->output_function)(s1, filter->data));
+			} else if (filter->to->no_encoding == mbfl_no_encoding_sjis2004 && (s1 >= 0xA1 && s1 <= 0xDF)) {
+				CK((*filter->output_function)(s1, filter->data));
 			} else {
 				CK(mbfl_filt_conv_illegal_output(c, filter));
 			}