PURPOSE: To obtain a laser beam machine of high reliability by generating a light beam, machining a work piece shifting a light beam from a current position to a target position in response to a device to generate the current position of the light beam, and its target position, and the current position and the target position.

CONSTITUTION: A laser beam machine 20 has a laser generator 22 which generates a laser beam 24, and executes machining a work piece. Based on a current position and a target position in the X axis direction of the laser beam 24, a X-PID controller 34a generates a X control signal. The X control signal is amplified by a X amplifier 40a and sent to X motor 38a. The X motor 38a operates and shifts a X carrier 42a, and then displaces a X mirror 44a linearly along the X axis toward the target position. Upon settled positioning of the X mirror 44a, the laser beam 24 generated in the laser generator 22 is made incident on the X mirror 44a, and the laser beam 24 proceeds toward the work piece. The operation in Y axis is made likewise. Thereby, the positioning of work piece is made, and a laser work of high reliability is performed.