To prevent layered products from being separated scatteringly by machining a hole, the axis of which is parallel to the axis of a fixing pin and the diameter of which is smaller than the shaft diameter of the fixing pin in the inside of the fixing pin to lessen the fixing force of the fixing pin after the end of perforating a printed circuit board.

After the end of perforating work for fixing electronic parts to a layered product, a hole with a diameter(d) is bored in the axis of a pin 24. When a hole 26 is machined in the pin 24, the radial rigidity of the pin 24 is lowered. Accordingly, when the diameter of the pin 24 before press-in and the diameter(d) of a hole 25 of a laminated board are suitably selected, the diameter of the hole 25 is returned to the diameter D1 by machining the hole 26, so that the pin 24 can be engaged with the hole 25 by frictional force based on the elastic energy of the pin 24. The pin 24 having moderate rigidity left prevents a layered product from being separated scatteringly, so that the layered product where perforating is ended can be easily recovered automatically.