A semiconductor laser device capable of high output is provided. A semiconductor laser diode includes: a substrate; and a semiconductor stacked structure, which is formed on the substrate through crystal growth. The semiconductor stacked structure includes: an n-type (Alx1Ga(1-x1))0.51In0.49P cladding layer and a p-type (Alx1Ga(1-x1))0.51In0.49P cladding layer; an n-side Alx2Ga(1-x2)As guiding layer and a p-side Alx2Ga(1-x2)As guiding layer, which are sandwiched between the cladding layers; and an active layer, which is sandwiched between the guiding layers. The active layer is formed of a quantum well layer including an AlyGa(1-y)As(1-x3)Px3 layer and a barrier layer including an Alx4Ga(1-x4)As layer that are alternatively repetitively stacked for a plurality of periods.