diff --git a/ChangeLog b/ChangeLog
index 20c6b95525..3eb9ffea4c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Jul 13 10:50:12 2016  Martin Duerst  <duerst@it.aoyama.ac.jp>
+
+	* enc/iso_8859_13.c, test/ruby/enc/test_case_comprehensive.rb:
+	  Implement non-ASCII case conversion for ISO-8859-13, by Kanon Shindo.
+
 Wed Jul 13 10:31:39 2016  Martin Duerst  <duerst@it.aoyama.ac.jp>
 
 	* enc/iso_8859_13.c, enc/windows_1257.c: Split Windows-1257 from
diff --git a/enc/iso_8859_13.c b/enc/iso_8859_13.c
index f2c763ff8b..4ba4c2b10f 100644
--- a/enc/iso_8859_13.c
+++ b/enc/iso_8859_13.c
@@ -217,6 +217,55 @@ get_case_fold_codes_by_str(OnigCaseFoldType flag,
 	     flag, p, end, items);
 }
 
+#ifdef ONIG_CASE_MAPPING
+static int
+case_map (OnigCaseFoldType* flagP, const OnigUChar** pp,
+					 const OnigUChar* end, OnigUChar* to, OnigUChar* to_end,
+					 const struct OnigEncodingTypeST* enc)
+{
+  OnigCodePoint code;
+  OnigUChar *to_start = to;
+  OnigCaseFoldType flags = *flagP;
+
+  while (*pp<end && to<to_end) {
+    code = *(*pp)++;
+    if (code==SHARP_s) {
+      if (flags&ONIGENC_CASE_UPCASE) {
+	flags |= ONIGENC_CASE_MODIFIED;
+	*to++ = 'S';
+	code = (flags&ONIGENC_CASE_TITLECASE) ? 's' : 'S';
+      }
+      else if (flags&ONIGENC_CASE_FOLD) {
+	flags |= ONIGENC_CASE_MODIFIED;
+	*to++ = 's';
+	code = 's';
+      }
+    }
+    else if ((EncISO_8859_13_CtypeTable[code] & BIT_CTYPE_UPPER)
+	     && (flags & (ONIGENC_CASE_DOWNCASE|ONIGENC_CASE_FOLD))) {
+      flags |= ONIGENC_CASE_MODIFIED;
+      code = ENC_ISO_8859_13_TO_LOWER_CASE(code);
+    }
+    else if (code==0xB5)  ;
+    else if ((EncISO_8859_13_CtypeTable[code]&BIT_CTYPE_LOWER)
+	     && (flags&ONIGENC_CASE_UPCASE)) {
+      flags |= ONIGENC_CASE_MODIFIED;
+      if (code==0xB8 || code==0xBA || code==0xBF) {
+        code -= 0x10;
+      }
+      else {
+        code -= 0x20;
+      }
+    }
+    *to++ = code;
+    if (flags&ONIGENC_CASE_TITLECASE)  /* switch from titlecase to lowercase for capitalize */
+      flags ^= (ONIGENC_CASE_UPCASE|ONIGENC_CASE_DOWNCASE|ONIGENC_CASE_TITLECASE);
+  }
+  *flagP = flags;
+  return (int)(to-to_start);
+}
+#endif   /* ONIG_CASE_MAPPING */
+
 OnigEncodingDefine(iso_8859_13, ISO_8859_13) = {
   onigenc_single_byte_mbc_enc_len,
   "ISO-8859-13",  /* name */
@@ -237,7 +286,7 @@ OnigEncodingDefine(iso_8859_13, ISO_8859_13) = {
   0,
   ONIGENC_FLAG_NONE,
 #ifdef ONIG_CASE_MAPPING
-  onigenc_single_byte_ascii_only_case_map,
+  case_map,
 #endif   /* ONIG_CASE_MAPPING */
 };
 ENC_ALIAS("ISO8859-13", "ISO-8859-13")
diff --git a/test/ruby/enc/test_case_comprehensive.rb b/test/ruby/enc/test_case_comprehensive.rb
index 8d202ca148..5796c5172c 100644
--- a/test/ruby/enc/test_case_comprehensive.rb
+++ b/test/ruby/enc/test_case_comprehensive.rb
@@ -257,7 +257,7 @@ class TestComprehensiveCaseFold
   generate_ascii_only_case_mapping_tests 'ISO-8859-7'
   generate_ascii_only_case_mapping_tests 'ISO-8859-9'
   generate_case_mapping_tests 'ISO-8859-10'
-  generate_ascii_only_case_mapping_tests 'ISO-8859-13'
+  generate_case_mapping_tests 'ISO-8859-13'
   generate_case_mapping_tests 'ISO-8859-14'
   generate_case_mapping_tests 'ISO-8859-15'
   generate_case_mapping_tests 'ISO-8859-16'