PURPOSE: To prevent the peeling of paint film in the parting line of a resin product by a method in which stripable paint is coated on the surface of a resin product, the stripable paint in the area to be coated is cut off and removed, the area to be coatd is with a paint, and the stripable paint in the other area is peeled off.

CONSTITUTION: A releasing agent 12, e.g., silicone, is coated on a lower mold corresponding to the surface to be painted of a resin product (a), and on the surface of the releasing agent 12, a stripable paint 13 composed of a given proportion of components is coated over the whole surface and dried. Then, an upper mold 14 whose surface is coated with a releasing agent 12 is covered on the lower mold 11, and a resin is cast into the molds for molding. Then, the stripable paint 13 coated on an area to be coated with a paint of the molded resin product (a) is dried and then cut off for removal. The part deprived of the stripable paint film is coated with a paint 15 and then dried. Thus, because the releasing agent 12 is peeled off when the paint 13 is peeled off, the coating of the resin product with a paint can be performed without the needs for deoiling operation.