Disclosed is a semiconductor device which is improved in output power efficiency since reflection by the substrate is reduced. This semiconductor device is also excellent in strength characteristics of a supporting substrate. Also disclosed is a method for producing such a semiconductor device. Specifically disclosed is a nitride semiconductor device wherein at least an n-type semiconductor layer, a light-emitting layer, a p-type semiconductor layer, a metal film layer and a plated metal plate are sequentially stacked in this order on a substrate. This nitride semiconductor device is characterized in that the metal film layer and the plated metal plate are partially formed on the p-type semiconductor layer. Also disclosed is a nitride semiconductor device having a structure wherein at least an n-type semiconductor layer, a light-emitting layer, a p-type semiconductor layer, a metal film layer and a plated metal plate are sequentially stacked in this order, the device characterized in that the metal film layer and the plated metal plate are partially formed on the p-type semiconductor layer and a light-transmitting material layer is formed on the p-type semiconductor layer in a region where the metal film layer and the plated metal plate are not formed.