PURPOSE: To provide a laser beam machine by which the correction of the deformation of fθ lens is performed, the moving speed is remarkably improved and the machine is greatly miniaturized.

CONSTITUTION: The machine is provided with a laser oscillator 1, a second reflection mirror 3 which is arranged on the optical axis of the laser beam and whose angle against the optical axis is changeable, a third reflection mirror 4 which is arranged as such that the rotary axis is provided at a twisted position rotated at right angle against the rotary axis of the second reflection mirror and whose angle is changeable, and the fθ lens 9 by which the laser beams reflected by the second and the third reflection mirrors are converged. In addition, on the optical axis between the laser oscillator and the fθ lens, a first reflection mirror 2 is arranged in a movable state while the angle of the first reflection mirror 2 against the incident beam is maintained, and the extent, speed and direction of the movement of this first reflection mirror are controlled.