A semiconductor laser diode capable of further improving temperature characteristics while sufficiently preventing a laser beam emission end surface portion from thermal destruction through a window structure is obtained. This semiconductor laser diode comprises an active layer having a window structure on a laser beam emission end surface portion and a p-type layer, formed on the surface of the active layer, containing Mg and Zn as impurities. The impurity concentration of Zn contained in the p-type layer is larger than the impurity concentration of Mg contained in the p-type layer.