PURPOSE: To ensure a high mass-productivity at a lower cost in the production of a wrist watch case eliminating the grinding process by painting the outer surface of a ground film formed on the surface of a cast skin of the body of the case made of a relatively soft metal.

CONSTITUTION: A wrist watch case 1 is cast using a relatively soft metal such as zinc as material. A ground film is formed on the surface of the cast skin thereof and pinted to finish. The body 2 of the wrist watch case 1 is made of a zinc die cast or the like and a formed film 3 uniformly formed on the surface of case skin thereof as a ground film on the surface of which a pint film 4 is applied. This method in which a ground film is directly applied on the surface of the cast skin and painted to finish provide a smooth surface without making any cast defect visible and thus enables the production of a wrist watch case with an excellent mass-productivity at a low cost with a higher yield eliminating the need for any grinding process.