An n-type buffer layer composed of n-type GaN, an n-type cladding layer composed of n-type AlGaN, an n-type optical confinement layer composed of n-type GaN, a single quantum well active layer composed of undoped GaInN, a p-type optical confinement layer composed of p-type GaN, a p-type cladding layer composed of p-type AlGaN, and a p-type contact layer composed of p-type GaN are formed on a substrate composed of sapphire. A current blocking layer formed in an upper portion of the p-type cladding layer and on both sides of the p-type contact layer to define a ridge portion is composed of a dielectric material obtained by replacing some of nitrogen atoms composing a Group III-V nitride semiconductor with oxygen atoms.