A nitride semiconductor device is provided. In the device, first and second conductivity type nitride layers are formed. An active layer is formed between the first and second conductivity type nitride layers. The active layer includes at least one quantum barrier layer and at least one quantum well layer. Also, a current spreading layer is interposed between the first conductivity type nitride layer and the active layer. The current spreading layer has an In content greater than the quantum well layer of the active layer.