Abstract: A cooling apparatus used, for instance, for a laser which is low in the consumption of energy and can be made small in size. The cooling apparatus includes: an outside air - water heat exchanger (or outside air cooler 15) as a first cooler; a refrigerant - water heat exchanger (or refrigerating cooler 27) as a second cooler; an outside air temperature sensor (22) for detecting an outside air temperature; and a control section (5) which, according to an outside air temperature, selects a refrigerator-cooler joint use mode for operating both the outside air cooler (15) and the refrigerating cooler (27), or an outside air cooler single use mode for operating only the outside air cooler (15) with the refrigerating cooler (27) stopped.