The invention provides a Group III nitride semiconductor light-emitting device in which the strain in the light-emitting layer is relaxed, thereby attaining high light emission efficiency, and a method for producing the device. The light-emitting device of the present invention has a substrate, a low-temperature buffer layer, an n-type contact layer, a first ESD layer, a second ESD layer, an n-side superlattice layer, a light-emitting layer, a p-side superlattice layer, a p-type contact layer, an n-type electrode N1, a p-type electrode P1, and a passivation film F1. The second ESD layer has pits X having a mean pit diameter D. The mean pit diameter D is 500 Å to 3,000 Å. An InGaN layer included in the n-side superlattice layer has a thickness Y satisfying the following condition: −0.029×D+82.8≦Y≦−0.029×D+102.8.