PURPOSE: To accurately drill a hole to a guide mark by accurately aligning the center of an X-ray device.

CONSTITUTION: A multilayered laminated board 9 in which a guide mark is provided is irradiated with X-rays from the X-ray irradiation source 2 of an X-ray device 1 and the X-ray image of the board 9 is projected on a monitor TV set 6 through an X-ray image pickup tube 3 and X-ray camera 4 and, at the same time, the center of the device 1 is found by processing the image. Then the center of the guide mark is brought nearer to the center of the device 1 by moving the device 1 composed of the source 2, tube 3, camera 4, etc., or the board 9. By repeating such operations one more time or a plurality of times, the center of the device 1 is accurately found against the guide mark. Then a hole is dug to the guide mark with a drilling device 7 by moving the device 7 which moves together with the device 1 in accordance with the data.