PURPOSE: To obtain a novel structure of a stripe type semiconductor laser which uses GaAs as a substrate and of which a band gap of an active layer is narrower than that of the GaAs.

CONSTITUTION: Clads 11, 12 and 21 on the opposite side to a substrate have a projecting stripe part 21 provided in parallel to the part of an active layer in which a current is injected in the shape of a stripe, and constituted of AlGaInP partially at least, and a light radiating layer 32 containing GaInP is formed above the parts 11 and 12 of the clads not having the projecting stripe part 21. The thickness of the parts 11 and 12 of the clads except the projecting stripe part is made the one allowing a laser oscillation light to be transmitted into the light radiating layer.