A cooling device includes at least two cooling units, each cooling unit including a plate-shaped cold plate extending in a horizontal direction, a radiator extending in a first direction perpendicular to the horizontal direction and having a plurality of plate-shaped fins which, on the cold plate, is disposed parallel to a second direction perpendicular to the first direction, and a pump which supplies a refrigerant liquid to the cold plate and the radiator, in which the pump is adjacent to the radiator and is disposed in the second direction of the radiator, and the pump of one first cooling unit of the two cooling units faces the other second cooling unit of the two cooling units in the second direction or in a third direction orthogonal to the first direction and the second direction.