A submersible aeration apparatus includes an air passage formed on a pump chamber to draw air into the pump chamber. A suction port formed on a lower side of the pump chamber draws liquid into the pump chamber. An impeller draws air through the air passage and liquid through the suction port. An ejection passage ejects the air and liquid. The impeller includes a main plate portion to cover a connection port connecting the air passage to the pump chamber. A vane portion protrudes downward from a lower surface of the main plate portion on the suction port side. The main plate portion has a cut-out part connecting the air passage and the pump chamber, and a groove part recessed from an upper surface of the main plate portion toward the lower surface and extending from an inner peripheral side toward an outer peripheral side of the main plate portion.