PURPOSE: A spindle motor is provided to hold a rotor supporting unit on a base plate by fixing the rotor supporting unit into the indentation groove of the base plate. CONSTITUTION: A rotor supporting unit(20) supports a rotor to be rotatably. The rotor supporting unit is fixed on a base plate(10). A protrusion(22) and a loading part are arranged on the rotor supporting unit. The protrusion is inserted into the insertion hole of the base plate. Indentation groove(12) is recessed around the insertion hole. The loading part is loaded on the base plate.
