An apparatus processes a fabric by repeated brushing on itself includes a process tumbler, provided with a feed duct for feeding the fabric in open-width form continuously between an infeed port and an outfeed port of the feed duct. An adjustment device for adjusting the passage section of the duct and associated with at least one of the ports. The adjustment device causes the passage section to be narrowed so that the fabric, which reaches the port in open-width form and is made to pass through a port in a first feed direction, is bunched into rope form and then allows the fabric, when made, to pass in the opposite direction through the narrowed passage section. The fabric is subtended by the other, wide port of the feed duct, to be stretched out from the rope form to the open-width form.