An edge-emitting semiconductor laser includes a resonator structure having an active layer. A low reflection three-layer film is provided on in emitting edge face of the resonator structure and a high reflection multi-layer film is provided on a rear edge face of the resonator structure. The low reflection three-layer film is formed in an exemplary embodiment by sequentially stacking a first Al.sub.2O.sub.3 layer having a thickness of 10 nm, an Si.sub.3N.sub.4 film having a thickness of 190 nm, and a second Al.sub.2O.sub.3 layer having a thickness of 10 nm.