A method of fabricating a nitride semiconductor laser comprises preparing a substrate having a plurality of marker structures and a crystalline mass made of a hexagonal gallium nitride semiconductor. A catalyst comprising an amine compound represented by the formula and an amine compound represented by the formula is used as an amine catalyst for curing a polyisocyanate compound. The primary spring can be a coil spring that surrounds an air helper spring. The web portion as well as the flange portion are provided with holes located in a common plane, perpendicular to the longitudinal direction of the girder.