diff --git a/scim-wnn/src/romkan.cpp b/scim-wnn/src/romkan.cpp
index b280040..57b6e37 100644
--- a/scim-wnn/src/romkan.cpp
+++ b/scim-wnn/src/romkan.cpp
@@ -313,7 +313,7 @@
  */
 bool Romkan::inputEvent(const KeyEvent &key)
 {
-    if (isprint(key.code) && (!key.is_alt_down()) && (!key.is_control_down())) {
+    if (key.get_ascii_code() && (!key.is_alt_down()) && (!key.is_control_down())) {
         if (key.get_ascii_code() == ' ') return(false);
         insert(key.get_ascii_code());
         return(true);