A method for finishing an exterior surface of an injection-molded product is provided, in which a metal layer is formed on the exterior surface of the injection-molded product, a photoresist layer is formed on the metal layer, a photomask is placed on the photoresist layer, light is projected onto the photomask, and remaining parts of the metal layer and the photoresist layer except for parts corresponding to a pattern formed on the photomask are removed by etching.