To perform distance adjustment between a workpiece and a laser beam machining head with high accuracy and in real time.

The laser beam machining apparatus 10 includes: an XY table 30 on which a workpiece 20 is placed; a height fine-adjustment section 50 for executing a fine adjustment of the height position of the workpiece 20, with a plurality of piezoelectric elements 40 for vertical driving arranged in parallel on the XY table 30, by bringing the upper end of the plurality of piezoelectric elements 40 into contact with the lower face of the workpiece 20; a laser beam machining head 60 for irradiating a machining face of the workpiece 20 with a laser beam from the above; an XY table driving section 70 for moving the XY table 30 in the horizontal direction (XY direction); a height sensor 80 for measuring a distance between the laser beam machining head 60 and the machining face of the workpiece 20; and a controller 90 which selectively drives the piezoelectric elements 40 based on the distance data measured by the height sensor 80 and which controls so that a distance between the laser beam machining head 60 and the machining surface of the workpiece 20 coincides with the focal length or an image-forming distance of the machining head 60.