A light-emitting device is equipped with a GaN substrate; an n-type AlxGa1-xN layer on a first main surface side of the GaN substrate; a p-type AlxGa1-xN layer positioned further away from the GaN substrate than the n-type AlxGa1-xN layer; and a multi-quantum well (MQW) positioned between the n-type AlxGa1-xN layer and the p-type AlxGa1-xN layer. In the light-emitting device, the p-type AlxGa1-xN layer side is down-mounted and light is emitted from a second main surface, which is the main surface opposite from the first main surface of the GaN substrate. The second main surface of the GaN substrate includes a region on which cavities and projections are formed. Also, the light-emitting device includes an n-electrode formed on the second main surface of the GaN substrate 1 and a protective film formed to cover the side wall of the n-electrode.