Resin-molded lens having no sink marks and process for producing same

A resin-molded lens for an automotive lamp, said lens having a light transmitting surface formed with a cut out area, said cut out area defining a wide lens surface part and a narrow lens surface part, said wide lens surface part having a thin lens surface portion bounded on its outer periphery by a thick structural support portion, said support portion being formed integrally with at least part of said thin lens surface portion, the improvement wherein a thick structural portion for said narrow surface part is formed of a first resin material in a first resin injection step and said wide lens surface part, comprising said thin lens portion and said support portion at its outer periphery and said narrow surface part comprising only said thin lens surface portion without a support portion, is formed of a second resin material in a second resin injection step separate from said first resin injection step, said thin lens surface portion of said narrow surface part being disposed over and formed integral with said structural portion and being substantially free of sink marks.