To provide metallic parts such as valves and couplings, which are increased in adhesion strength and excellent in sealable properties and corrosion resistance over a long period by a method wherein the metallic part, such as a valve and a coupling, and a resin pipe are sealed and connectable and molding of resin adhered to the outer peripheral surface of the metallic part, such as a valve and a coupling is practicable.

A metallic body 11 such as a valve and a coupling, and a synthetic resin body 12 as polyorefin resin such as modified polybudene resin are joined together with an epxoyresin adhesive 13 serving as an inclusion. The metallic body 11 and the epoxy resin adhesive 13 are adhered together through an oxide film formed by applying oxidation treatment on the joining surface of the metallic body 11. The epoxy resin adhesive 13 and the synthetic resin body 12 are adhered together through a mixture powder material of modified low melt point polyorefin resin and a low melt point activator.