To precisely conduct alignment without forming an alignment mark.

When a work 8 is placed on a X goniotable 9, a surface shape of a prescribed region of the work 8 upper face is image-picked up by a CCD camera 9, and is supplied to an image processing part 33 to be stored. When completing machining of an upper face of the work 8, the X goniotable 9 is rotated in a prescribed angle, a left side face of the work 8 is moved to a position facing an objective lens 7. The image processing part 33 image-picks up a surface shape of an object to be picked up by a CCD camera 27. By comparing the image stored in the previous processing, a deviation of a position of the work 8 is calculated. Further, a motor control part 35 drives each motor corresponding to the deviation calculated and controls so as to bring the work 8 to a prescribed position.