A drain pump is provided that reduces the operating noise when the head is low. The drain pump has a pump casing, and an impeller. The pump casing has a drain inlet for sucking in drain water at a lower end part and a drain outlet for discharging drain water at a side part. The impeller has a shaft part extending in a vertical direction inside the pump casing, a main blade disposed on the outer circumferential side of the shaft part, an auxiliary blade disposed on the lower side of the main blade, and a disc shaped dish part disposed between the main blade and the auxiliary blade. The dish part has an annular partition part extending upward from the outer circumferential edge part of the main blade, which is disposed at a position lower than the upper end part of the partition part.