A nonaqueous battery comprising a positive electrode, a negative electrode and an electrolyte in a battery can having a cap, said cap having an opening and a sealing metal plate whose circumferential portion is supported by the cap. The sealing metal plate is supported by the cap via a layer of polymer material selected from the group consisting of a copolymer of an olefin and an acrylate ester or methacrylate ester which is grafted with maleic anhydride, a copolymer of an olefin and acrylic acid or methacrylic acid, and a copolymer of an olefin and an acrylate ester or methacrylate ester which is modified with a silane compound.