A method of forming a via hole reaching a bonding pad in a wafer having an insulating film constituting a plurality of devices on the front surface of a substrate and bonding pads on each of the devices by applying a pulse laser beam to the rear surface of the substrate, the method comprising the steps of: forming a non-through hole reaching the insulating film formed on the substrate by applying a pulse laser beam to the rear surface of the substrate; forming an insulating film on the inner wall of the hole which is formed in the substrate by the first step; and forming a via hole reaching a bonding pad by applying a pulse laser beam to the hole having the insulating film which is formed on the inner wall by the insulating film forming step.