Contoured step sections and contoured grooves along the step sections are formed on a grille body. The grille body is subjected to chemical plating. Since the grooves have narrow bottoms, the bottoms remain unplated, so that a chemical plating layer is formed on the entire surface of the grille body except for the bottoms. The grille body having the chemical plating layer formed thereon is then subjected to an electroplating step having a plurality of steps. An undercoat plating layer is formed on the chemical plating layer formed on the portions where decorative plating is to be applied. The chemical plating layer formed on the portions where no decorative plating is to be applied is dissolved with a predetermined solution. Subsequently, a general electroplating layer is formed on the undercoat plating layer. Thus, the chemical plating layer and the electroplating layers are formed only on the to-be-plated portions. The plated portions are covered with an electroforming mask, and a coating is applied onto the exposed portions to form a coating layer, where the edges of the electroforming mask can be registered with the edges of the plating layer. Accordingly, the boundaries between the coating layer and the plating layer can clearly be defined.