A bonded piston seal, which comprises a metal ring, and a rubbery elastomer seal as vulcanization-bonded thereto expect the sliding site along which a mating seal member slides, where the rubbery elastomer seal is partially bonded to the metal ring through an adhesive layer, wherein the adhesive layers comprises (a) an underlayer adhesive layer comprising a phenol resin and an epoxy resin, and (b) an overlayer adhesive layer comprising a phenol resin, a halogenated polymer, and a metal oxide. Not only the distinguished initial adhesiveness, but also the distinguished water-resistance can be obtained by providing (a) the underlayer adhesive layer of the afore-mentioned components and (b) the overlayer adhesive layer of the afore-mentioned components.