This semiconductor laser apparatus includes a base, a plurality of electrodes arranged along a first direction on an upper surface of the base, a plurality of semiconductor laser devices bonded to respective upper surfaces of the plurality of electrodes, emitting laser beams in a second direction, and a photodetector having a photosensitive surface arranged in a region of the base in a third direction relative to the plurality of semiconductor laser devices. An electrode arranged in a position other than end portions in the first direction and a fourth direction, of the plurality of electrodes has an extraction wiring portion arranged on the photosensitive surface of the photodetector.