The present invention relates to a semiconductor laser apparatus having a structure for preventing the corrosion of a refrigerant flow path in a heat sink and for cooling a semiconductor laser array stably over a long period of time. The semiconductor laser apparatus comprises a semiconductor laser stack in which a plurality of semiconductor laser units are stacked, a refrigerant supplier, a piping for connecting these components, and a refrigerant flowing through these components. The refrigerant supplier supplies the refrigerant to the semiconductor laser stack. The refrigerant is comprised of fluorocarbon. Each of the semiconductor laser units is constituted by a pair of a semiconductor laser array and a heat sink. The heat sink has a refrigerant flow path.