Abstract: A semiconductor light emitting element, semiconductor light emitting device or image display device includes a wavelength converter for converting a wavelength into another, optical reflector having a wavelength selectivity and a light absorber having a wavelength selectivity, which are disposed in a predetermined positional relation, to prevent external leakage of primary light and to extract secondary light made by wavelength-converting the primary light with a very high efficiency. By using a semiconductor light emitting element for ultraviolet emission, or by combining it with a fluorescent material or any other appropriate material having a wavelength converting function, various kinds of applications, such as illuminator, having a remarkably long-life light source can be made. The semiconductor light emitting element preferably has a emission wavelength near 330 nm, and preferably uses BGaN in its light emitting layer.