To provide a means for speedup and efficiency of a pulling-out work of a metal screw fastened by a fastening article made of a thermoplastic resin and a dismountable work.

By applying an electric voltage between arbitrary two points of the metal screw, the fastening article made of the thermoplastic resin brought into tight contact with the metal screw is softened by a Joule heat generated in the metal screw itself, to pull up the head part of the metal screw while it is held and to pull it out. In another way, by applying an electric voltage between arbitrary two points of a washer made of a shape-memory alloy, the washer made of the shape-memory alloy itself is changed to a high temperature mother phase by a Joule heat generated in the washer itself, to release the washer made of the shape-memory alloy from a predetermined fastened position and to make a fastening function lose.