A semiconductor laser device having a waveguide constructed in a stack of layers including, on a substrate that is transparent and has a refractive index n.sub.s for laser light, a first clad layer of a refractive index n.sub.c1, a second clad layer of a refractive index n.sub.c2, a third clad layer of a refractive index n.sub.c3, a first conductivity type guide layer of a refractive index n.sub.g, an active quantum well layer, a second conductivity type guide layer, a second conductivity type clad layer, and a second conductivity type contact layer deposited in that order, wherein the waveguide has an effective refractive index n.sub.e, and the relationship n.sub.c2<(n.sub.c1, n.sub.c3)