diff --git a/honoka/src/romkan.cpp b/honoka/src/romkan.cpp
index a44b0ef..7fb21f2 100644
--- a/honoka/src/romkan.cpp
+++ b/honoka/src/romkan.cpp
@@ -394,7 +394,7 @@
     if (buf.length()) buf = buf.substr(0,buf.length() - 1);
     // BS���˥Хåե���Ƭ��ʸ����������
     // ���ΰ�ʸ�������󥰥�Х��ȤǤʤ��ä������˴���
-    if (pos && (!removeRemainder)) {
+    if (pos && (!removeRemainder) && ((pos - buf.size()) > 0)) {
         String s = utf8_wcstombs(text.substr(pos - (buf.length() + 1),1));
         if (s.length() == 1) {
             buf = s + buf;