A multi-beam semiconductor laser apparatus includes three or more stripe semiconductor laser emission units which are arranged on a substrate, isolation grooves which separate the semiconductor laser emission units from each other, and pad electrodes which are disposed on outer sides of the outermost semiconductor laser emission units. The isolation grooves are formed between the pad electrodes and the semiconductor laser emission units adjacent to the pad electrodes and between adjacent semiconductor laser emission units. A distance between two isolation grooves formed on outer sides of the outermost semiconductor laser light emission units is smaller than a distance between two isolation grooves formed on both sides of inner ones of the semiconductor laser light emission units.