A reactor cooling device includes a housing, a reactor arranged in the housing, and a rotating body which is rotationally located below the reactor in the housing. The rotating body and the reactor are located so as to at least partially overlap with each other in a previously selected one of turning radius directions of the rotating body. A part of the rotating body is immersed in the coolant stored in the housing. The reactor cooling device is configured to cause a part of the coolant splashed by the rotation of the rotating body to be in contact with the reactor to thereby cool the reactor.