A temporary part is fixed to a base by using an adhesive layer to which fillers are mixed at a predetermined density. When the temporary part is heated, heat is applied to the fillers and the adhesive layer. At a temperature equal to or higher than the glass-transition temperature of the adhesive agent, the heated adhesive layer is thermally contracted so as to release remaining stress, and on the other hand, the heated fillers are thermally expanded. In this manner, the peel-off strength between the adhesive layer and the base (or the temporary part) is reduced, and the disassembly is facilitated.