To reduce rotation period, while the rotary shaft of a dynamic pressure motor is brought into contact with a bearing and reduce the wear of the shaft and bearing.

A velocity command signal and a velocity detection signal related to a dynamic pressure bearing motor are compared with each other by a comparison unit 1 and a deviation (e) is outputted. A driver unit 3 controls a drive current applied to the dynamic pressure bearing motor M so as to reduce the deviation (e). The revolution detection unit FG detects the number of revolution of the motor M. A 1st velocity detection unit 7 outputs the velocity detection signal corresponding to the revolution in accordance with the detection signal of the revolution detection unit FG to the comparison unit 1. A 2nd velocity detection unit 9 compares its detected velocity with a reference velocity, corresponding to the revolution of 1/2-1/4 of the rated revolution of the motor M, and if the detected velocity is reduced below the reference velocity, outputs a brake signal S to the driver unit 3. The driver unit 3 controls the brake of the dynamic pressure bearing motor M based on with the brake signal S.