A semiconductor laser device (10) includes a resonant cavity (12) in which a quantum well active layer (11) made up of barrier layers of gallium nitride and well layers of indium gallium nitride is vertically sandwiched between at least light guide layers of n- and p-type aluminum gallium nitride. An end facet reflective film (13) is formed on a reflective end facet (10b) opposite to a light-emitting end facet (10a) in the resonant cavity (12). The end facet reflective film (13) has a structure including a plurality of unit reflective films (130), each of which is made up of a low-refractive-index film (13a) of silicon dioxide and a high-refractive-index film (13b) of niobium oxide. The low-and high-refractive-index films are deposited in this order on the end facet of the resonant cavity (12).