A gallium nitride-based compound semiconductor light-emitting device having an n-type semiconductor layer, a light-emitting layer and a p-type semiconductor layer formed in this order on a substrate. Each layer includes a gallium nitride-based compound semiconductor, the light-emitting device has a negative electrode and a positive electrode provided on the n-type semiconductor layer and on the p-type semiconductor layer, respectively, the positive electrode is at least partially formed of a transparent electrically conducting film, the transparent electrically conducting film is at least partially in contact with the p-type semiconductor layer, a semiconductor metal mixed layer containing a Group III metal component is present on the semiconductor side surface of the transparent electrically conducting film, and the thickness of the semiconductor metal mixed layer is from 0.1 to 10 nm.