diff --git a/builder.py b/builder.py
index 3b57d04b..7230c01f 100644
--- a/builder.py
+++ b/builder.py
@@ -61,7 +61,7 @@ class ExtensionBuilder(build_ext):
 
         cfg = "Debug" if self.debug else "Release"
         # cfg = 'Debug'
-        build_args = ["--config", cfg]
+        build_args = ["--config", cfg, "-j", "4"]
         install_args = ["--config", cfg]
 
         cmake_args += ["-DCMAKE_BUILD_TYPE=" + cfg]