To autoclave a hollow fiber filter cartridge many times to reutilize the same many times by providing first and second open end parts to the tube dividing a filtrate conduit.

In a filter cartridge 601, a fluid enters the hole 7' of a casing 50' to be filtered by bores through the walls of porous hollow fibers 35' and the filtrate flows toward first and second open end parts 615, 616 at the same time. The porous hollow fibers 35' from which the fluid issues enter the closed collecting chamber corresponding to a container at the second open end part 616. Then, the fluid is allowed to flow to the first open end part 615 and a lower manifold through a central filter conduit 603. The filtered fluid issuing from the porous hollow fibers 35' to the first open end part 615 and the fluid issuing from the filter conduit 603 shaped by the tube 60 dividing the filter conduit together flow to the outside of the lower mainfold.