PURPOSE: Title device in which a cutter is provided with inclination at a specific angle on the peripheral wall of the part with expanded diameter which follows the compression part to release rapidly the compresive pressure, thus expanding and softening tissues of fibrous material to break with simple mechanism.

CONSTITUTION: A fibrous material of animal or plant with a water content of 5W 60wt% comes through the transferring part A to the compression part B' where it is pressurized and heated by a plurality of stripe projections 11 on the inner wall of the main body and rotation of the tapered screw blades and further strongly compressed in part B". The tightly sealed material is extruded into part with expanded diameter 8 where it is made into small pieces by cutter 10 that is composed of gradually inclined projections that have angles of 15W30°C in the same direction as the rotation of the shaft with the shaft axis from the inlet side. The small pieces are extruded toward slit where they are thrown out into the atmosphere instantly and the explosive expansion of water in the material is caused by the steep pressure reduction to effect the efficient softening and breaking. The temperature, pressure and treating time at the compression part B are 200W400°C, 15W22.5kg/cm2 and 3W20sec.