A manufacturing method comprises: a material preparation step of forming a metal layer on a front side surface of a submount bar body which is to face a laser bar on which a front side electrode and a back side electrode are formed, to prepare a submount bar on which the laser bar is to be mounted; a jig installation step of installing the submount bar and the laser bar that are provided in plural number alternately stacked each other on an installation jig; a bonding step of bonding the metal layer and the back side electrode by increasing the temperature of the installation jig; and a protective film forming step of forming a protective film on cleaved end faces of the laser bar in a protective film forming apparatus using the installation jig in which the submount bars and the laser bars are installed, after the bonding step.