The principal surface of a substrate made of a group III-V compound semiconductor material is about a (100) plane. A light emitting lamination structure is disposed on the principal surface. In the light emitting lamination structure, a quantum well layer is sandwiched by a pair of carrier confinement layers made of a semiconductor material having a band gap wider than a semiconductor material of the quantum well layer. The pair of carrier confinement layers are sandwiched by a pair of clad layers made of a semiconductor material having a band gap wider than the band gap of the semiconductor material of the carrier confinement layers. Thicknesses of the quantum well layer and the carrier confinement layers, as well as compositions of the semiconductor materials thereof, are set such that light emission recombination of electrons and holes occurs in the quantum well layer and not in the carrier confinement layers.