COOLING DEVICE

A cooling device uses siphon circulation whose heat source is an object-to-be-cooled installed in a vehicle to circulate refrigerant to the object-to-be-cooled, the cooling device including: a tank that is disposed above the object-to-be-cooled and stores the refrigerant; an outflow path that opens to the inside of the tank and through which the refrigerant flows out; a passage member that extends from the inside to the outside of the tank, with an open end of an inside section of the passage member positioned inside the tank being positioned above an opening of the outflow path; and identifying means that is provided at an outside section of the passage member positioned outside the tank and by which the position of the open end inside the tank can be identified.