1 files changed, 1 insertions, 1 deletions
diff --git a/ext/nkf/nkf.c b/ext/nkf/nkf.c
index ba8ffc978f..c11a042c57 100644
--- a/ext/nkf/nkf.c
+++ b/ext/nkf/nkf.c
@@ -80,7 +80,7 @@ rb_encoding* rb_nkf_enc_get(const char *name)
 int nkf_split_options(const char *arg)
 {
     int count = 0;
-    char option[256];
+    unsigned char option[256];
     int i = 0, j = 0;
     int is_escaped = FALSE;
     int is_single_quoted = FALSE;