Disclosed herein is a spindle motor including: a base provided with a rotating shaft and a fitting part coupled with a sleeve supporting the rotating shaft and provided with a protruding part protruded to the outside along a circumference of an outer peripheral surface of the fitting part. According to the present invention, the structure in which the inner diameter surface is assembled in the base can be implemented without a separate additional part and the structure in which the inner diameter surface of the core is assembled in the base can be implemented, thereby improving the rotation torque.