A light emitting element comprising at least: a first light reflecting layer formed on a surface of a substrate , wherein the substrate comprises a GaN substrate or a sapphire substrate; a laminated structural body made of a first compound semiconductor layer , an active layer , and a second compound semiconductor layer formed on the first light reflecting layer ; and a second electrode and a second light reflecting layer formed on the second compound semiconductor layer , wherein the laminated structural body is configured from a plurality of laminated structural body units, a light emitting element unit is configured from each of the laminated structural body units, the surface of the substrate has a step-like shape, one laminated structural body unit is formed above a portion of the substrate, the portion being equivalent to one tread, and a resonator length in the light emitting element unit is different in every light emitting element unit , wherein the first compound semiconductor layer is grown from the substrate by epitaxial lateral overgrowth, ELO, wherein the first light reflecting layer is a distributed Bragg reflector, DBR, layer made of a dielectric multilayer film, wherein the first light reflecting layer in every light emitting element unit is mutually spatially separated; wherein the second electrode and the second light reflecting layer are mutually separated among different light emitting element units ; wherein the light emitting element units are configured to output a plurality of types of desired wavelengths; wherein the first light reflecting layer includes a dielectric film containing at least a nitrogen (N) atom, the dielectric film serving as an uppermost layer of the dielectric multilayer film; wherein the uppermost layer included in first light reflecting layer is formed by applying nitriding treatment, the surface layer containing the at least a nitrogen (N) atom. a first light reflecting layer formed on a surface of a substrate , wherein the substrate comprises a GaN substrate or a sapphire substrate; a laminated structural body made of a first compound semiconductor layer , an active layer , and a second compound semiconductor layer formed on the first light reflecting layer ; and a second electrode and a second light reflecting layer formed on the second compound semiconductor layer , wherein the laminated structural body is configured from a plurality of laminated structural body units, a light emitting element unit is configured from each of the laminated structural body units, the surface of the substrate has a step-like shape, one laminated structural body unit is formed above a portion of the substrate, the portion being equivalent to one tread, and a resonator length in the light emitting element unit is different in every light emitting element unit , wherein the first compound semiconductor layer is grown from the substrate by epitaxial lateral overgrowth, ELO, wherein the first light reflecting layer is a distributed Bragg reflector, DBR, layer made of a dielectric multilayer film, wherein the first light reflecting layer in every light emitting element unit is mutually spatially separated; wherein the second electrode and the second light reflecting layer are mutually separated among different light emitting element units ; wherein the light emitting element units are configured to output a plurality of types of desired wavelengths; wherein the first light reflecting layer includes a dielectric film containing at least a nitrogen (N) atom, the dielectric film serving as an uppermost layer of the dielectric multilayer film; wherein the uppermost layer included in first light reflecting layer is formed by applying nitriding treatment, the surface layer containing the at least a nitrogen (N) atom. <EOS>