A cooling apparatus includes a heat receiver that evaporates a low pressure heat transfer medium. The apparatus includes a compressor that compresses the evaporated heat transfer medium in a gas phase state, and a condenser that condenses the compressed heat transfer medium. The apparatus includes a receiver tank that receives and stores at least one of the heat transfer medium from any place in a flow path of the medium in the gas phase state that returns the medium to the heat receiver and the condensed medium in a liquid phase state. The apparatus includes an air storage tank that air separated from the heat transfer medium. The apparatus includes a liquid level controller that controls a liquid level in the receiver tank such that the heat transfer medium is stored in the receiver tank at a predetermined liquid level height.