diff --git a/tools/infer/infer.py b/tools/infer/infer.py
index b06a51bd55a0ab448886aff3fcd21398e90d439d..0962bcca41a5ca210759f56527732864fbb99ea8 100644
--- a/tools/infer/infer.py
+++ b/tools/infer/infer.py
@@ -85,7 +85,7 @@ def create_operators():
 
 
 def preprocess(fname, ops):
-    data = open(fname).read()
+    data = open(fname, 'rb').read()
     for op in ops:
         data = op(data)
 
diff --git a/tools/infer/py_infer.py b/tools/infer/py_infer.py
index 8236bc6f96d0c547d0ef685315df1ce5af58c628..512c16b38df94b2ab335890f46c107f65cdc4dd3 100644
--- a/tools/infer/py_infer.py
+++ b/tools/infer/py_infer.py
@@ -67,7 +67,7 @@ def create_operators():
 
 
 def preprocess(fname, ops):
-    data = open(fname).read()
+    data = open(fname, 'rb').read()
     for op in ops:
         data = op(data)