To provide a method of efficiently bonding a metal and a non-metallic structural product to a polytetrafluoroethylene.

A composite comprising the polytetrafluoroethylene and a structural material (a polymer, a metal, ceramic, leather, or wood) are bonded with a cured mixed material of a tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer, a polyethylene-oxide modified silicone polymer coupling agent, and an oxygen-radical-containing copolymer (an epoxy polymer, a phenoxy polymer, or a hydroxylated diamine-diepoxide derivative copolymer). A bonding plane of a polytetrafluoroethylene part of the composite is etched (chemical etching, electron beam etching, laser etching, or plasma etching), before an uncured mixed material is coated thereto. The composite is useful for a production of a seal, a gasket, a chemical resistant hose, an O-ring, and a diaphragm for a pump.