diff -ruN scim-1.4.4.org/src/scim_iconv.cpp scim-1.4.4/src/scim_iconv.cpp
--- scim-1.4.4.org/src/scim_iconv.cpp	2005-08-15 21:45:46.000000000 +0900
+++ scim-1.4.4/src/scim_iconv.cpp	2006-12-10 10:39:17.360221573 +0900
@@ -96,11 +96,11 @@
     iconv_t new_iconv_to_unicode;
 
     if (scim_is_little_endian ()) {
-        new_iconv_from_unicode = iconv_open (encoding.c_str (), "UCS-4LE");
-        new_iconv_to_unicode = iconv_open ("UCS-4LE", encoding.c_str ());
+        new_iconv_from_unicode = iconv_open (encoding.c_str (), "UCS-2LE");
+        new_iconv_to_unicode = iconv_open ("UCS-2LE", encoding.c_str ());
     } else {
-        new_iconv_from_unicode = iconv_open (encoding.c_str (), "UCS-4BE");
-        new_iconv_to_unicode = iconv_open ("UCS-4BE", encoding.c_str ());
+        new_iconv_from_unicode = iconv_open (encoding.c_str (), "UCS-2BE");
+        new_iconv_to_unicode = iconv_open ("UCS-2BE", encoding.c_str ());
     }
 
     if (new_iconv_from_unicode == (iconv_t) -1 ||
@@ -143,17 +143,23 @@
     size_t src_buf_size = 0;
     size_t ret;
 
+    ucs2_t *ucs2src = new ucs2_t[src_len];
+    for (int i = 0; i < src_len; i++) {
+	ucs2src[i] = (ucs2_t)src[i];
+    }
+
     iconv (m_impl->m_iconv_from_unicode, 0, &src_buf_size, 0, &dest_buf_size); 
 
     char *dest_buf_ptr = dest_buf;
-    ICONV_CONST char *src_buf_ptr = (ICONV_CONST char*) src;
+    ICONV_CONST char *src_buf_ptr = (ICONV_CONST char*) ucs2src;
 
     dest_buf_size = SCIM_MAX_BUFSIZE * MB_LEN_MAX;
-    src_buf_size = src_len * sizeof (ucs4_t);
+    src_buf_size = src_len * sizeof (ucs2_t);
 
     ret = iconv (m_impl->m_iconv_from_unicode, &src_buf_ptr, &src_buf_size, &dest_buf_ptr, &dest_buf_size); 
     dest.assign (dest_buf, dest_buf_ptr);
 
+    delete[] ucs2src;
     return ret != (size_t) -1;
 }
 
@@ -171,18 +177,24 @@
     char dest_buf [SCIM_MAX_BUFSIZE * MB_LEN_MAX];
     size_t src_buf_size = 0;
     size_t dest_buf_size = 0;
+
     size_t ret;
+    ucs2_t *ucs2src = new ucs2_t[src_len];
+    for (int i = 0; i < src_len; i++) {
+	ucs2src[i] = (ucs2_t)src[i];
+    }
 
     iconv (m_impl->m_iconv_from_unicode, 0, &src_buf_size, 0, &dest_buf_size); 
 
     char *dest_buf_ptr = dest_buf;
-    ICONV_CONST char *src_buf_ptr = (ICONV_CONST char*) src;
+    ICONV_CONST char *src_buf_ptr = (ICONV_CONST char*) ucs2src;
 
-    src_buf_size = src_len * sizeof (ucs4_t);
+    src_buf_size = src_len * sizeof (ucs2_t);
     dest_buf_size = SCIM_MAX_BUFSIZE * MB_LEN_MAX;
 
     ret = iconv (m_impl->m_iconv_from_unicode, &src_buf_ptr, &src_buf_size, &dest_buf_ptr, &dest_buf_size); 
 
+    delete[] ucs2src;
     return ret != (size_t) -1;
 }
 
@@ -198,20 +210,30 @@
     if (m_impl->m_iconv_to_unicode == (iconv_t) -1) return false;
 
     ucs4_t dest_buf [SCIM_MAX_BUFSIZE];
+    ucs2_t ucs2_dest_buf [SCIM_MAX_BUFSIZE];
 
     size_t dest_buf_size = 0;
     size_t src_buf_size = 0;
     size_t ret;
+    int  i;
 
     iconv (m_impl->m_iconv_to_unicode, 0, &src_buf_size, 0, &dest_buf_size); 
 
-    char *dest_buf_ptr = (char*) dest_buf;
+    char *dest_buf_ptr = (char*) ucs2_dest_buf;
     ICONV_CONST char *src_buf_ptr = (ICONV_CONST char*) src;
 
-    dest_buf_size = SCIM_MAX_BUFSIZE * sizeof (ucs4_t);
+    dest_buf_size = SCIM_MAX_BUFSIZE * sizeof (ucs2_t);
     src_buf_size = src_len;
 
     ret = iconv (m_impl->m_iconv_to_unicode, &src_buf_ptr, &src_buf_size, &dest_buf_ptr, &dest_buf_size); 
+
+    size_t dest_cnt = (SCIM_MAX_BUFSIZE * sizeof (ucs2_t) - dest_buf_size)
+		/ sizeof (ucs2_t);
+		
+    for (i = 0; i < dest_cnt; i++) {
+	dest_buf[i] = (ucs4_t)ucs2_dest_buf[i] & 0x0000ffff;
+    }
+    dest_buf_ptr = (char *)&dest_buf[i];
     dest.assign (dest_buf, (ucs4_t*) dest_buf_ptr);
 
     return ret != (size_t) -1;
@@ -234,16 +256,21 @@
     size_t dest_buf_size = 0;
     size_t ret;
 
-    iconv (m_impl->m_iconv_from_unicode, 0, &src_buf_size, 0, &dest_buf_size); 
+    ucs2_t *ucs2src = new ucs2_t[src_len];
+    for (int i = 0; i < src_len; i++) {
+	ucs2src[i] = (ucs2_t)src[i];
+    }
+    iconv (m_impl->m_iconv_to_unicode, 0, &src_buf_size, 0, &dest_buf_size); 
 
     char *dest_buf_ptr = (char*) dest_buf;
-    ICONV_CONST char *src_buf_ptr = (ICONV_CONST char*) src;
+    ICONV_CONST char *src_buf_ptr = (ICONV_CONST char*) ucs2src;
 
     src_buf_size = src_len;
-    dest_buf_size = SCIM_MAX_BUFSIZE * sizeof (ucs4_t);
+    dest_buf_size = SCIM_MAX_BUFSIZE * sizeof (ucs2_t);
 
     ret = iconv (m_impl->m_iconv_to_unicode, &src_buf_ptr, &src_buf_size, &dest_buf_ptr, &dest_buf_size); 
 
+    delete[] ucs2src;
     return ret != (size_t) -1;
 }
 
diff -ruN scim-1.4.4.org/src/scim_types.h.in scim-1.4.4/src/scim_types.h.in
--- scim-1.4.4.org/src/scim_types.h.in	2005-01-05 22:41:10.000000000 +0900
+++ scim-1.4.4/src/scim_types.h.in	2006-12-10 10:39:17.358667879 +0900
@@ -43,6 +43,7 @@
 #else
     typedef uint32 ucs4_t;
 #endif
+typedef uint16 ucs2_t;
 
 typedef std::basic_string<char> String;
 typedef std::basic_string<ucs4_t> WideString;