An LD with an improved heat dissipating function in the edge regions is disclosed. The LD provides the core region including the active layer and extending whole of the substrate, and the ridge waveguide structure on the core region that extends in a direction along which the light generated in the active layer is guided. The ridge waveguide structure is buried by a thick resin layer in both sides thereof, but the resin layer is removed in the edge regions close to respective facets of the LD.