The present invention provides a semiconductor laser device for improving temperature characteristics of waveguide structures and realizing stable light emitting patterns and high output, and a method for making the same. The semiconductor laser device (1) comprises: an n-type clad layer (5) laminated on a substrate (2); an active layer (6) laminated on the n-type clad layer (5); a p-type clad layer (7) laminated on the active layer (6); and a plurality of waveguide structures (8) formed on the p-type clad layer (7) and having a ridge of a horn shape in top view. In this configuration, a divider (29) is formed between adjacent waveguide structures (8), and the divider (29) comprises: a groove (30) dividing the active layer (6); and a heat dissipation material (34) filled in the groove (30) and having a thermal conductivity higher than a thermal conductivity of a semiconductor layer (4).