A method for manufacturing a semiconductor device includes forming a semiconductor laminated structure on a substrate as a wafer including semiconductor laser structures; forming a first groove between the semiconductor laser structures on a major surface of the wafer; separating the wafer to laser bars including at least two of the semiconductor laser structures arrayed in a bar shape, after forming the first groove; forming a second groove in the first groove of the laser bars, the second groove having a width no wider than the first groove; and separating one of the laser bars into respective semiconductor lasers along the second groove.