diff --git a/python/tvm/_ffi/runtime_ctypes.py b/python/tvm/_ffi/runtime_ctypes.py
index 06f2d4c7e6b6..570a24ed5dd3 100644
--- a/python/tvm/_ffi/runtime_ctypes.py
+++ b/python/tvm/_ffi/runtime_ctypes.py
@@ -140,6 +140,8 @@ def __init__(self, type_str):
             self.lanes = ctypes.c_uint16(-int(arr[2]))
         elif len(arr) > 1:
             self.lanes = ctypes.c_uint16(int(arr[1]))
+        else:
+            self.lanes = 1
         bits = 32
 
         if head.startswith("int"):