A deaeration apparatus of the present invention includes a tank that stores a liquid to be deaerated, a circulation pipe having one end connected to an outflow port of the tank and the other end connected to an inflow port of the tank, a pump that is provided in the circulation pipe and sucks and feeds the liquid in the tank, and a foaming device that is provided in the circulation pipe and causes the liquid to flow through a throttle portion having a narrowed flow path section to generate air bubbles from the liquid, wherein deaeration of the liquid stored in the tank is performed by circulating the liquid between the tank and the foaming device.