diff --git a/src/Encoder/Encoder.php b/src/Encoder/Encoder.php
index 5444c28..71c18ad 100644
--- a/src/Encoder/Encoder.php
+++ b/src/Encoder/Encoder.php
@@ -163,7 +163,7 @@ private static function getAlphanumericCode(int $code) : int
     private static function chooseMode(string $content, string $encoding = null) : Mode
     {
         if (null !== $encoding && 0 === strcasecmp($encoding, 'SHIFT-JIS')) {
-            return self::isOnlyDoubleByteKanji($content) ? Mode::KANJI() : Mode::BYTE();
+            return Mode::BYTE();
         }
 
         $hasNumeric = false;