A method of forming holes into a printed circuit board whereby when a hole is formed into the printed circuit board by using an energy beam such as a laser beam or the like, a focal point position of the beam is moved with the progressing of the hole forming process. To move the focal point position of the beam with the progressing of the hole forming process when a hole is formed into the printed circuit board by using an energy beam such as a laser beam or the like, a mechanism to move a converging optical system in the direction of the optical axis is provided. Also provided is a method of checking a penetrating state of a through hole in the case where a through hole is worked into a circuit pattern portion of a printed circuit board by using an energy beam such as a laser beam and where the beam is irradiated from the surface of the printed circuit board and the material constructing the printed circuit board is fused and discharged and penetrated to the back surface, thereby forming a through hole.