An inductor includes a base and a winding assembly. The base includes an outer frame, a middle part and a connecting part. The outer frame has a first upper surface. The middle part has a second upper surface. The connecting part is connected with the outer frame and the middle part and has a third upper surface. The connecting part, the outer frame and the middle part collectively define a receptacle. The winding assembly is accommodated within the receptacle. The second upper surface of the middle part is disposed at a higher level with respect to the first upper surface of the outer frame. A first height is defined by the level difference between the second upper surface and the third upper surface. A second height of the winding assembly is smaller than the first height, so that a fourth upper surface of the winding assembly is disposed at a lower level with respect to the second upper surface after the winding assembly is accommodated within the receptacle.