A cup portion of a base member includes a cylindrical portion and a bottom plate portion. The cylindrical portion is arranged to be coaxial or substantially coaxial with a central axis extending in a vertical direction. The bottom plate portion is defined integrally with the cylindrical portion, and is arranged to close a lower portion of the cylindrical portion. A bearing mechanism is arranged inside of the cup portion. An outer circumferential surface of the bearing mechanism and an inner circumferential surface of the cylindrical portion have an adhesive layer arranged therebetween. In one preferred embodiment of the present invention, a communicating hole passing through the cylindrical portion in a direction that crosses an axial direction is defined in the vicinity of a junction of the cylindrical portion and the bottom plate portion. In another preferred embodiment of the present invention, the base member includes a communicating hole passing through the bottom plate portion in the axial direction.