A cooling device is provided with a cooling unit that includes a cold plate extending in a first direction; a pump and a tank disposed on one side in a second direction perpendicular to the first direction of the cold plate; and a partition member extending in the first direction and covering the cold plate on one side in the second direction. The cold plate includes a first refrigerant flow path through which a refrigerant flows in the first direction. The pump includes a pump chamber where a rotating body is accommodated. The tank includes a tank chamber storing the refrigerant and a first tank hole part communicating with the pump chamber. The partition member, including a first hole part that communicates the first flow path and the tank chamber, is provided on one side in the first direction with respect to the first hole part.