The objective is to efficiently suppress the temperature of the hottest parts within the core and within each coil. The reactor includes a magnetic core having an annular shape, a primary coil unit externally fitted on the core, and a secondary coil unit externally fitted on the core. The primary coil unit includes a primary coil and a primary-side coating that coats the primary coil. The secondary coil unit includes a secondary coil and a secondary-side coating that coats the secondary coil. The reactor further includes a cooling container. The cooling container houses the core, the primary coil unit, and the secondary coil unit. Within the cooling container, a liquid coolant flows from an inlet towards an outlet in such that the liquid level of the coolant is higher than the upper ends of all of the core, the primary coil, and the secondary coil.