A cooling device for a railroad vehicle that cools a heat generating body housed in a storage box set on the floor of the railroad vehicle includes a heat conduction plate configuring a part of a side surface of the storage box, the heat generating body being mounted on one surface side of the heat conduction plate, a plurality of heat pipes inclined to project from the other surface side to an upper side of the heat conduction plate, a plurality of fins fixed to the plurality of heat pipes, and a cover that includes opening sections, and covers the cooling device. A total of areas of the opening sections located on the base side of the heat pipes is formed larger than a total of areas of the opening sections located on the distal end portion side of the heat pipes.