A method for manufacturing a semiconductor laser device includes forming a laminate having a semiconductor layer of a first conductivity type, an active layer and a semiconductor layer of a second conductivity type. The waveguide region is formed to guide light perpendicular to the direction of width by restricting the light from spreading in the direction of width in the active layer, such that the semiconductor laser device has a first waveguide region and a second waveguide region. The first waveguide region is formed to confine light within the limited active layer by means of a difference in the refractive index between the active layer and the regions on both sides of the active layer by limiting the width of the active layer. In forming the second waveguide region, light is confined therein by providing effective difference in refractive index in the active layer.