Hem part processing body and hem portion machining method

A case of forming a hem portion with a metal plate and synthetic resin plate, to provide a hem portion workpiece is high retention force for fixing the position of the plate. A hem portion workpiece includes a first member having an inner bent portion end of the plate-like member containing a thermoplastic resin is formed at a portion that is bent, plate-like containing a metal material an outer bent portion end of the member is formed in a portion that is bent, the outer bent portion is arranged to surround the inner bent portion, the end portion is disposed inside the inner bent portion , it is formed weak portion on the inner surface of the inner bent portion. .The