diff --git a/clip_vision.py b/clip_vision.py
index 3775cd5..dd341df 100644
--- a/clip_vision.py
+++ b/clip_vision.py
@@ -49,7 +49,10 @@ class ClipVision(NNOperator):
     @property
     def device(self):
         if self._device is None:
-            self._device = torch.device(self._device_id)
+            if self._device_id < 0:
+                self._device = torch.device('cpu')
+            else:
+                self._device = torch.device(self._device_id)
         return self._device
 
     def __call__(self, image: 'Image'):