diff --git i/src/seqdiag/tests/test_rst_directives.py w/src/seqdiag/tests/test_rst_directives.py
index c3affce..4c184b8 100644
--- i/src/seqdiag/tests/test_rst_directives.py
+++ w/src/seqdiag/tests/test_rst_directives.py
@@ -177,15 +177,6 @@ class TestRstDirectives(unittest.TestCase):
         self.assertEqual(1, len(doctree))
         self.assertEqual(nodes.image, type(doctree[0]))
 
-    def test_setup_inline_svg_is_true_with_multibytes(self):
-        directives.setup(format='SVG', outputdir=self.tmpdir, inline_svg=True)
-        text = (".. seqdiag::\n"
-                "\n"
-                "   あ -> い")
-        doctree = publish_doctree(text)
-        self.assertEqual(1, len(doctree))
-        self.assertEqual(nodes.raw, type(doctree[0]))
-
     def test_setup_inline_svg_is_true_and_width_option1(self):
         directives.setup(format='SVG', outputdir=self.tmpdir,
                          nodoctype=True, noviewbox=True, inline_svg=True)