diff --git a/scim-wnn/src/romkan.cpp b/scim-wnn/src/romkan.cpp
index 6fbccb5..29bf546 100644
--- a/scim-wnn/src/romkan.cpp
+++ b/scim-wnn/src/romkan.cpp
@@ -124,7 +124,7 @@
 
     // �ơ��֥�򸡺��������Ϥ��롣
     unsigned int i = 0;
-    while(RomkanTable[i] != "") {
+    while(strcmp(RomkanTable[i],"") != 0) {
         if (buf == String(RomkanTable[i])) {
             if (String(RomkanTable[i + 1]) == "") {
                 return(text); // ��α���롣
@@ -138,7 +138,7 @@
         }
         i += 2;
     }
-    buf.clear();
+    if (buf.length()) buf = buf.substr(1);
     return(text);
 }