Inner circumferential surfaces of a rotor holder and a turntable are in contact with an outer circumferential surface of a shaft. This stabilizes coaxiality of both the rotor holder and the turntable with respect to the shaft. An upper cover portion of the rotor holder includes fixing holes. The turntable includes fixing projections arranged to extend through the fixing holes to be in contact with a lower surface of the upper cover portion. A base end portion of each fixing projection is arranged at a level higher than that of an upper end portion of a corresponding one of the fixing holes. Therefore, even if dimensional errors of the rotor holder and the turntable cause a radial displacement between any fixing projection and a corresponding one of the fixing holes, the rotor holder and the turntable can be fixed to each other while maintaining coaxiality therebetween.