A semiconductor laser device is characterized in that an angle of inclination
formed by the side surfaces of a ridge portion and a lower part of the ridge portion
is at least 70 and not more than 117, a p-type cladding layer is made
of AlX1Ga1-X1As, a first current blocking layer is made of
AlX2Ga1-X2As, the distance between an emission layer and
the first current blocking layer satisfies the relation of t0.275/(1-(X2-X1))
assuming that t represents the distance, and a lower width W of the ridge portion
is at least 2 m and not more than 5 m.
