SELECTION PROCESSING APPARATUS

PURPOSE:To realize highly accurate correction processing without extra irradiation to the area other than the correcting region by automatically measuring sizes of defective region on the photomask and automatically setting the correcting region based on such measurement. CONSTITUTION: An image of photomask 1 is enlarged with an objective lens 2 and it is then focused to the pick-up surface of television camera 7 through an intermediate lens 6. The size of defective region of this image is measured with a measuring circuit 25 and sizes obtained by the measuring circuit 25 are sent to the comparison and adjusting circuit 26. A pulse motor 10 which drives a plate 9 forming an aperture 10 for the input sizes, the moving distance is caused to correspond by counting a number of pulses and when these match, the pulse motor 10 is stopped. Thereby, the aperture 19 corresponds to sizes of the processing region of the photomask 1 with high accuracy and the processing region is processed with high accuracy with the laser beam sent from the laser 11 in the processing part through the aperture 19.