A pump includes: a housing in which a pump chamber that is a columnar space is formed, the pump chamber being provided with a suction-side groove and a discharge-side groove that are formed as recesses; an outer rotor rotatably disposed in the pump chamber and having internal teeth on an inner periphery of the outer rotor; and an inner rotor disposed radially inward of the internal teeth of the outer rotor, and having external teeth formed on an outer periphery of the inner rotor and meshed with the internal teeth of the outer rotor. A portion of an inner edge of the discharge-side groove is located radially inward of a locus of tooth tips of the internal teeth of the outer rotor, the portion being located in a second half region of the discharge-side groove in a rotational direction of the inner rotor and the outer rotor.