A semiconductor laser apparatus includes a substrate, a vertical-cavity surface-emitting semiconductor laser diode (VCSEL) including a first and second mirror layers of a first and second conduction types, respectively, an active region between the first and second mirror layers, a first and second electrode layers electrically connected with the first and second mirror layers, respectively, and at least one Zener diode including a first and second semiconductor regions of a first and second conduction types, respectively, and a third and fourth electrode layers electrically connected with the first and second semiconductor regions, respectively. The second semiconductor region is formed in a portion of the first semiconductor region and forms a PN junction with the first semiconductor region. The VCSEL and the Zener diode are formed on the substrate. The first and second electrode layers are electrically connected with the fourth and third electrode layers, respectively.