An object of the present invention is to provide a variable displacement vane pump (1) capable of further reducing a pulse pressure. A vane pump (1) includes a cam ring (33). The cam ring (33) is annularly formed, and defines a plurality of pump chambers (38) on an inner peripheral side thereof in cooperation with a rotor (31) and vanes (32). An inner peripheral surface (330) of the cam ring (33) is formed in such a manner that, assuming that a confinement region refers to a region between an end portion of an intake port (221) and an end portion of a discharge port (222), at a timing when the pump chamber (38) communicates with or is disconnected from the discharge port (222) on one side corresponding to one of confinement regions or a timing close thereto, a change in a volume change amount of the pump chamber (38) on another side corresponding to the other of the confinement regions has an extreme value in a direction for reducing a change in a discharge amount at the time of the above-described communication/disconnection.