To suppress adhesion of impurities to a semiconductor light emitting element, there is provided a nitride-based semiconductor light emitting element including: a laminated body having a first cladding layer, an active layer formed over the first cladding layer, and a second cladding layer formed over the active layer; and a dielectric film with a thickness of 3 μm or more that is formed on the side surface of the laminated body on the side where light is emitted and that covers at least a first side surface of the active layer.