PURPOSE: To prevent an interruption of reaction between copper in a plating layer and sulfur in rubber at the initial stage of adhesion of the metal and the rubber, with realizing improvement in resisting properties against moisture and heat, by vulcanizing and adhering a metal coated with a ternary alloy plating layer of copper-zinc- cobalt of a specified composition whereby the cobalt containing ratio is gradually increased from the surface to the inside of the layer in a depth direction, and a rubber obtained by adding a predetermined rate of sulfur into natural rubber or synthetic isoprene rubber.

CONSTITUTION: In a metal which is coated with a ternary alloy plating layer of copper- zinc-cobalt having copper 60W75weight%, cobalt 2W10weight% and zinc the rest, the cobalt containing ratio at the most surface of the plating layer is 0W5weight% which ratio is gradually increased to the depth 50W200 of the plating layer from the most surface. The ratio is generally constant in the plating layer deeper than the depth 50W200 from the most surface. Accordingly, in the case where rubber including natural rubber or synthetic isoprene rubber as its main component and sulfur, with or without addition or organic acid cobalt salt, silica or resorcin as an adhesion accelerator, is vulcanized and adhered with the metal, the adhesive property at the early stage is not obstructed, but the deterioration of the adhesive property during the use of the rubber product can be restricted.