Metal part, and surface treating method thereof

In a metal part in which a rubber is adhered to a portion or the whole of a surface thereof, and a surface treating method of the metal part to improve adhesive property between the metal and the rubber, to make it easy to form a surface roughness in a portion of a metal part, and to achieve an improvement in the surface roughness and mold maintenance property, a reduction of working cost, and a reduction of man hour. A surface roughness for increasing adhesive property between the metal and the rubber is formed in a portion of the metal part to which the rubber is adhered, and the surface roughness is transcribed from a mold to the metal part by providing with a surface roughness in the mold. A magnitude of the surface roughness is preferably set to be 10 μm or more and less than 60 μm.