In a nitride semiconductor laser bar including a group III-V nitride semiconductor layer, on the front-side cavity end face, a separation layer of aluminum nitride is laid, and further on the separation layer, an end face coating film of aluminum oxide is laid. Likewise, on the rear-side cavity end face, a separation layer of aluminum nitride is laid, and further on the separation layer, an end face coating film of an aluminum oxide/TiO2 multilayer film is laid.