PURPOSE: To easily manufacture and to increase a current constriction effect of a semiconductor laser by forming a state that a reverse mesa ridge is superposed on a substrate, positioning an active layer in the ridge disposed on the substrate, and disposing current constriction units on both sides of the layer.

CONSTITUTION: One current constriction unit is formed in the narrowest bottom of width dimension of the lower end of a reverse mesa ridge 2 at the top of an active layer 13, and another current constriction unit is formed in the narrowest bottom of width dimension of the lower end of a reverse mesa ridge 3 at the bottom of the layer 13. The surface of a buffer layer 11, the sides of the ridges 2, 3, and the upper surface are covered with SiO2 films 4, the center surface of the ridge 3 is etched to partly remove the film 4, the surface center of a cap layer 16 is exposed, and electrodes 5, 6 are formed on the whole surface of the film 4 and the whole lower surface of a substrate 1. Thus, since a double reverse mesa structure is provided, the current constriction effect is increased to less reduce a current density, to reduce a threshold value current, to enhance an output, and a stable laser oscillation is obtained in a basic lateral mode.