A nitride semiconductor device having excellent ESD tolerance, by preventing uneven distribution of the electric current in the p-side nitride semiconductor layer. The p-side nitride semiconductor layer (40) comprises, from the active layer (30) side, (a) a p-side wide band gap layer (12) containing a p-type impurity and (b) a three-layer structure (15) comprising a first p-side nitride semiconductor layer (16), a second p-side nitride semiconductor layer (17), and a third p-side nitride semiconductor layer (18).