To provide a spacing for interposition of an adhesive between an inner panel and an outer panel, while setting up a welding site in an inner panel to carry out abutting of the outer panel, and welds each other.

A seat surface part 25 of an inner panel 20 is set as a welding site so that the seat surface part 25 can be welded to an outer panel in a surface contact state. Bringing the seat surface part 25 of the inner panel 20 into surface contact with an opposite flat plate part 41 of the outer panel 40 causes a spacing (equivalent site for interposing adhesive T2) for the interposition of the adhesive, in which an adhesive T2 for bonding is interposed, is formed between a plate-shaped base body 21 (inner panel 20) and the opposite flat plate part 41 (outer panel 40). It is thereby possible to provide the welding site at which the inner panel 20 and the outer panel are brought into contact with and welded to each other, and to provide a spacing (equivalent site for interposing adhesive T2) in which the adhesive T2 is to be interposed between the inner panel 20 and the outer panel 40.