The nitride semiconductor laser device includes a substrate, a nitride semiconductor layer having a first nitride semiconductor layer, an active layer, and a second nitride semiconductor layer stacked in this order on the substrate, and a ridge provided on a surface of the nitride semiconductor layer. The surface of the nitride semiconductor layer includes a generally flat part and first and second grooves which extend along the ridge in a resonator direction, the first groove being formed continuous to a first side surface of the ridge, the second groove being formed continuous to a second side surface of the ridge which is opposite to the first side surface