A optical scanner control method and a optical scanner capable of positioning a mirror at a high speed independently of a rocking angle, and a laser machining apparatus for irradiating a printed circuit board with a laser beam by use of the optical scanner to thereby perforate the printed circuit board. In order to operate an actuator for rocking the mirror based on a deviation of a current position from an commanded value, a change in gain of the actuator is measured in accordance with each rocking angle in advance, and the manipulated variable of the actuator is corrected to cancel the change in gain. Thus, the influence of the alteration of a torque constant in accordance with the rocking angle can be suppressed so that the response characteristic becomes uniform all over a scanning region, and the positioning speed can be improved.