In a spinning machine having sliver-resolving apparatus including a resolving roller, a first member and a second member cooperating with the first member to form a first sliver-feeding champing nip spaced from the resolving roller at an interval corresponding to the length of long fibers to be spun, one of such members being a driven roller for feeding sliver to the resolving roller, the improvement comprising a third member cooperating with the first member to form a second sliver-feeding champing nip spaced from the resolving roller at an interval corresponding to the length of short fibers to be spun, and selecting means for rendering said second clamping nip active or inactive on sliver being fed to the resolving roller.