Abstract: A shredding device is provided in which counterrotating parallel shafts carry interleaved cutting disks thereon. The rim of each cutting disk is of concave cross section so that cutting blade edges of acute angles are formed at the perimeter of each flat transverse surface of each disk. Also, a plurality of transverse grooves or notches are formed spaced along the rim of some of the disks. Cutting and shredding of material fed to the counterrotating disks is improved by virtue of the sharper blade cutting edges and because the notched disks tend to grab the material to be cut and forcibly draw it against the cutting edges of the counterrotating disks.