A first injection mechanism of an apparatus for molding articles injects coating material into a cavity defined in a clamped mold, thereby forming a predetermined coating on the inner surface of the cavity. After the coating material is injected into the cavity, a decompression mechanism lowers the pressure in the cavity through at least one vent. After the coating is formed on the inner surface of the cavity, a second injection mechanism injects molding material into the cavity. When the pressure in the cavity is being lowered, an opening-closing mechanism opens the vent. Before or during the injection of the molding material, the opening-closing mechanism closes the vent.