A cooling device includes: a refrigerant circulation loop configured to depressurizing the inside thereof, the refrigerant circulation loop includes, an evaporator that vaporizes a part of refrigerant by heat generated by an electronic component, a condenser that cools the refrigerant, and a pump that circulates the refrigerant, wherein a filling ratio of liquid refrigerant to a volume of the refrigerant circulation loop is configured to maintain a refrigerant circulation capability of the pump.