In a motor, a dynamic pressure gas bearing is prevented from seizing when the motor shaft and a sleeve contact each other. The number of rotations of a rotating body with respect to a case is maintained substantially constant both before and after contact. Auxiliary bearings are arranged in series with the gas bearing. A non-contact detent torque generation mechanism in parallel with the auxiliary bearings suppresses rotation in the auxiliary bearings. The sum of a predetermined detent torque generated by the torque generation mechanism during a rotation suppression time and the friction torque of the auxiliary bearings is smaller than the magnitude of an adhesion-time contact friction torque generated when the motor shaft and sleeve adhere to each other and is greater than the magnitude of a rotation-time viscous friction torque of the dynamic pressure gas bearing while the motor shaft and sleeve are spaced from each other.