A method of manufacturing semiconductor laser device including a GaN wafer includes forming a semiconductor layer on the GaN wafer and on which ridge portions are formed. Grooves are formed in the semiconductor layer such that each groove is disposed in line with the scribe marks, between each of the ridge portions and an upstream scribe mark. The grooves are curved and convex outwardly towards a downstream side, and each groove has an apex on a cleavage line. The side extending from the apex preferably does not form an angle of 60 degrees with respect to a cleavage direction or the cleavage line.