A reactor cooling structure includes: a plurality of reactors that are stacked on one another, each reactor including a coil configured to produce magnetic flux when energized; and a cooling mechanism that cools the plurality of reactors, wherein each of the reactors has an exterior member that has: heat radiation surfaces respectively on both sides of the corresponding one of the reactors in a stacking direction of the stacked reactors i.e. a first direction, the heat radiation surfaces of the exterior member of each of the reactors being arranged to cool the coil of the corresponding one of the reactors; the cooling mechanism includes a cooling flow path for directly cooling the first and second heat radiation surfaces of the exterior member of each of the reactors by a refrigerant.