A semiconductor laser including a semiconductor substrate and a multilayer structure formed upon the semiconductor substrate, the multilayer structure including an active layer, a pair of cladding layers between which the active layer is interposed, and a current confinement layer for injecting a current into a stripe-shaped predetermined region of the active layer. The current confinement layer comprises a first current blocking layer formed in regions thereof excluding a region corresponding to the predetermined region of the active layer. The first current blocking layer has a refractive index higher than a refractive index of the pair of cladding layers and an energy band gap larger than an energy band gap of the active layer.