An aeration apparatus includes an injection nozzle provided at one of the open ends of a main body formed in the shape of a cylinder. When the injection nozzle is immersed in a liquid, the main body stands upright such that the injection nozzle is on a lower side, and gas is injected inside the main body from the injection nozzle to disperse the gas. The injection nozzle is disposed such that a center line of an injection port formed at the tip of the injection nozzle intersects the inner flow channel surface at a position lower than a blade member disposed in the lowest stage, and such that the angle formed between the center line and the vertical direction is not greater than 45 degrees.