Abstract: The Capillary Dialyzer contains a housing (1) with a bundle of capillaries (2) contained within. There are between the capillaries threads (15) of a textured yarn assigned to the bundle of capillaries without connection to the individual capillaries. In the bundle of capillaries (2) is such a number of threads (15) which are distribued evenly over the cross section of the bundle so that the cross section of the dialyzate chamber is filled with the threads in a resilient and elastic way.