diff --git a/src/aijack/defense/paillier/torch_wrapper.py b/src/aijack/defense/paillier/torch_wrapper.py
index 8dc1e585..5a2bdea9 100644
--- a/src/aijack/defense/paillier/torch_wrapper.py
+++ b/src/aijack/defense/paillier/torch_wrapper.py
@@ -21,9 +21,9 @@ class PaillierTensor(object):
     """torch.Tensor-like object for Paillier Encryption"""
 
     def __init__(self, paillier_array):
-        if type(paillier_array) == list:
+        if isinstance(paillier_array, list):
             self._paillier_np_array = np.array(paillier_array)
-        elif type(paillier_array) == np.ndarray:
+        elif isinstance(paillier_array, np.ndarray):
             self._paillier_np_array = paillier_array
         else:
             raise TypeError(f"{type(paillier_array)} is not supported.")