Disclosed is a vane pump comprising a cam ring accommodated in a pump housing, a rotor accommodated rotatably with respect to a rotational shaft in the cam ring, and a plurality of vanes coupled to the rotor to discharge fluid, wherein the cam ring has a ring shaped inner profile varied between a maximum radius (Rmax) and a minimum radius (Rmin) in a circumferential direction with respect to the rotational shaft, and the ring shaped inner profile comprises: a cycloid curve passing through a maximum radius point; a circular arc passing through a minimum radius point; and a tangent line connecting the cycloid curve to the circular arc with a tangential curvature.