A ridge section constructed of a p-type second AlGaInP clad layer 8, a p-type GaInP interlayer 9 and a p-type GaAs cap layer 10 is formed on an etching stop layer 7. A step of not smaller than 0.13 μm is formed between the p-type interlayer 9 and the p-type second clad layer 8 by making the p-type interlayer 9 protrude in both widthwise directions beyond the p-type second clad layer 8. With this step, AlInP layers can be formed separately from each other on both sides of the ridge section and on the ridge section. Therefore, when the AlInP layer on the ridge section is removed by etching, an AlInP current constriction layer 13 located on both sides of the ridge section is reliably protected by a resist film and not over-etched. The AlInP current constriction layer 13 effectively puts a current constriction function into effect, so that a semiconductor laser device of low-threshold current and low-power consumption is obtained.