PURPOSE: To obtain the structure of the semiconductor light emitting device which can be practiced for the industry easily and in which a stable single lateral mode can be obtained by providing the semiconductor layer consisting of at least one of the compound of indium, gallium and phosphorus and the compound of indium, gallium, arsemic and phosphorus on the semiconductor substrate, and providing the region where the stripe-form thickness is different in said semiconductor layer.

CONSTITUTION: On the N type GaAs substrate 11, the N type In0.49Ga0.51P layer 12 is grown by liquid-phase epitaxial growth method. Next, a stripe-formed mask is arranged on the N type InGaP layer 12 by SiO2 followed by etching to form a stripe-form mesa. On the mesa-form N type InGaP layer 12, an N type Ga0.53 Al0.47As clad layer 13, a P type Ga0.34Al0.16As active layer 14, a P type Ga0.53 Al0.47As clad layer 15 and the N+ type GaAs cap layer 16 are grown. Just right on the stripe part of the N+ type GaAs cap layer 16, a P+ type region 17 is formed and further a P-side electrode 18 and an N-side electrode 19 are arranged. By cleavage and etc., the laser element is completed.