The present invention relates to a device, such as a carding machine, for processing fibers, said device comprising a cylinder, which is provided with a lining, and at least two carding segments which are arranged one after the other in the direction of rotation at least over an area of the circumference of said cylinder, each of said carding segments being provided with a toothed lining. The present invention aims at improving the efficiency of such a device especially in terms of fiber parallelization. In order to achieve this, the toothed linings of the carding segments are designed differently; when the fibers are engaged by the toothed lining of the carding segment constituting the upstream carding segment in the direction of rotation, the resultant influence on an individual fiber entrained by the circumference of the cylinder will be equal to or more intensive than the influence exerted when the fibers are engaged by the toothed lining of a carding segment constituting a downstream carding segment in the direction of rotation.