A method for producing a semiconductor optical device includes the steps of forming a semiconductor region including a ridge structure on a substrate; forming an insulating film on the semiconductor region; forming a non-photosensitive resin region on the insulating film, forming a first mask that defines a scribe area; forming the scribe area by etching using the first mask; after removing the first mask, forming an insulating layer by etching the insulating film, forming an electrode on the ridge structure and the non-photosensitive resin region to produce a substrate product; forming a scribe line on a surface of the semiconductor region in the scribe area of the substrate product; and cutting the product along the scribe line to form a semiconductor laser bar.