A method is for manufacturing a nitride semiconductor laser element including a substrate, a nitride semiconductor layer that is laminated on the substrate and that has a ridge on its surface, an insulating protective film, and an electrode that is electrically connected with the nitride semiconductor layer. The method includes forming the ridge; forming a monocrystalline first film from the side faces of the ridge to the nitride semiconductor layer on both sides of the ridge; and forming a second film containing polycrystalline or an amorphous substance over the first film thereby forming the insulating protective film.