PURPOSE: To cut large lumps of chips (turning) in the form of a permanent wave to such a size that they are automatically fed to a crusher to prepare the material to be crushed.

CONSTITUTION: This pretreatment device consists of a hopper 1 for receiving turning (a), a cylindrical part 3 whose upper part communicates with the lower part of the hopper 1 and which has a tapered part 4 on one end side and whose axial center line is horizontal, a rotary barrel 2 having a barrel part 2a which is opposed to the cylindrical inside of the cylindrical part 3 and a conical part 2b which is opposed to the inside of the tapered part 4 and is provided integrally with the barrel part 2a, a spiral feed blade 9 provided on the outer periphery of the rotary barrel 2 and having cutting blades 10 in the halfway of it, a driving means for turning and driving the rotary barrel 2 so that the feed direction of the feed blade 9 may be on the tapered art 4 side of the cylindrical part 3 and fixed blades 11 provided on the inside wall of the cylindrical part 3 on the side where the turning direction of the rotary drum 2 is downward.