Abstract: To automatically align a laser beam path with respect to an axis along which a movable carriage of a laser processing machine moves, the apparatus of this invention comprises means for detecting laser beam position at least when the carriage is positioned at a first and a second position, means for displaying the detected laser beam positions, and means for adjusting the mirror tilt angle. In the apparatus, the laser beam path is aligned with respect to the axis by actuating the mirror tilt angle adjusting means so that the second laser beam position on the display means is moved to coinside with the first laser beam position. The apparatus of this invention may comprise, instead of the display means, means for calculating an inclination angle of the laser beam with respect to the axis, based on the distance between the first and the second position, and distance between the first and the second laser beam position.