diff --git a/natto/mecab.py b/natto/mecab.py
index e9d7c90..e70b4a4 100644
--- a/natto/mecab.py
+++ b/natto/mecab.py
@@ -350,6 +350,8 @@ def __parse_tonodes(self, text, **kwargs):
                     self.lattice, bpos, self.MECAB_TOKEN_BOUNDARY)
 
                 for (token, match) in tokens:
+                    if token == '':
+                        continue
                     bpos += 1
                     if match:
                         mark = self.MECAB_INSIDE_TOKEN