To provide a screws suitable for disassembly of a product and provide a method to simply disassemble the product fastened by means of these screws.

A screw blank 2 is formed out of a metal material in which a hydrogen absorping substance is included in a certain mix proportion, and therefore, no hydrogen brittleness is generated when the screw 1 is exposed to hydrogen contained in the atmosphere or water at room temperature, and only when the screw 1 has got a high temperature, hydrogen embrittlement is promoted in its sub-neck part, and the screw is cut off in the sub-neck part. Because each screw 1 consists of the described metal material and is furnished with a protection film not occluding hydrogen, the screw 1 can be precluded from hydrogen embrittlement certainly in the ordinary service. Product fastened by such screws 1 consisting of the described metal material is installed in an atmosphere containing a specified concentration of hydrogen gas, and because it is arranged so that this atmosphere is kept at a high temperature for the specified time, it is possible to disassemble products in a great quantity and simply.