An internal gear pump includes a pump rotor (4) in which a meshing point between an inner rotor (2) having n teeth and an outer rotor (3) having (n+1) teeth is located rearward, in a rotational direction of the rotor, relative to an eccentric axis (CL) along which a center (OI) of the inner rotor and a center (OO) of the outer rotor are disposed. A tooth-surface curve of the outer rotor (3) near a meshing section thereof is formed by duplicating thereto a tooth-surface shape of the inner rotor (2) near a meshing section thereof.