In a motor including a chucking device for detachably holding a disk, the chucking device has a center case to which a central opening of the disk is inserted. The center case has a cylindrical portion coaxial with the center axis, a cover portion for covering an axial upper side of the cylindrical portion of the center case and a base portion fixed to the shaft-fixed portion of the rotor holder; resilient members received within the center case; and claw members remaining in contact with the respective resilient members, the claw members being movable radially to hold the disk in place. The center case is spaced apart from the rotor holder except for the base portion contacting with the shaft-fixed portion of the rotor holder.