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 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 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 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 atom.