diff --git a/requirements.txt b/requirements.txt
index 5e727be..f3c8941 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,4 @@
 sphinx>=1.5.0
 sphinx_rtd_theme
+sphinx-cjkspace
 pygments
diff --git a/source/conf.py b/source/conf.py
index 2c43702..3ec845d 100644
--- a/source/conf.py
+++ b/source/conf.py
@@ -32,7 +32,8 @@ import sys
 # ones.
 extensions = ['sphinx.ext.todo',
     'sphinx.ext.viewcode',
-    'sphinx.ext.githubpages']
+    'sphinx.ext.githubpages',
+    'sphinx_cjkspace.cjkspace']
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']