Abstract: An object of the present invention is to provide a water purification cartridge in which the decreased function of the hollow fiber membranes is restored by cleaning and of which the operating cost of a purification treatment of raw water decreases. The present invention provides a water purification cartridge comprising a hollow fiber membrane element comprising a plurality of hollow fiber membranes bent in a U-shape and a potting material for binding both ends of the hollow fiber membranes so as to maintain the open states of the hollow fiber membranes and a cylindrical hollow fiber membrane case for covering the hollow fiber membranes, wherein the hollow fiber membrane element is detachably installed in the hollow fiber membrane case so that a fluid-tight state is maintained between the primary side and the secondary side of the hollow fiber membranes.