A multibeam laser diode capable of improving heat release characteristics in the case of junction-down assembly is provided. Contact electrodes are provided respectively for protruding streaks of a laser diode device, and pad electrodes are provided to avoid the protruding streaks and the contact electrodes. The contact electrodes and the pad electrodes are connected by wiring electrodes, and the contact electrodes are covered with a first insulating film. Thereby, electric connection is enabled without straightly jointing the contact electrodes to a solder layer. A heat conduction layer configured of a metal is provided on the first insulating film, the heat conduction layer is jointed to the solder layer, and thereby the heat release characteristics are able to be improved even in the case of junction-down assembly.