To perform a fixing work and a filling work to a workpiece with a member to be embedded, made of aluminum material or the like, at low cost, by performing a lid forming work without using a different member.

A groove part extended inward from a surface and a convex part protruding from the surface along both sides or one side of the groove part are provided in a workpiece. A member to be embedded is disposed in the groove, and the convex part is subjected to plastic deformation to flow into the groove part and is integrated with an inner wall of the groove part, so that a lid portion of the groove part is formed.