diff --git a/pixelocr/config.py b/pixelocr/config.py
index 0a61b74..0388195 100644
--- a/pixelocr/config.py
+++ b/pixelocr/config.py
@@ -22,6 +22,7 @@ class Configuration(BaseConfiguration):
 
     min_body_height = 10
     min_word_distance = 15
+    space_width = 15
 
     diacritic_box_left = -3
     diacritic_box_right = +3
diff --git a/pixelocr/document.py b/pixelocr/document.py
index 0a445c9..c816ee8 100644
--- a/pixelocr/document.py
+++ b/pixelocr/document.py
@@ -28,8 +28,6 @@ from .utils import cached_property
 
 
 class Document(object):
-    SPACE_WIDTH = 15
-
     def __init__(self, dirname, ui, skip=0, limit=None, output_format='text'):
         super().__init__()
         self.dirname = dirname
@@ -61,7 +59,7 @@ class Document(object):
         return ''.join(self.output_format.format(glyph_data_seq))
 
     def recognize_line(self, line):
-        yield from [SPACE] * int(line.indent / self.SPACE_WIDTH)
+        yield from [SPACE] * int(line.indent / self.config.space_width)
         for glyph in line.glyphs:
             yield self.recognize_glyph(glyph)
         yield NEWLINE