PURPOSE: To provide a cutting device capable of sufficiently exhibiting cutting capacity even when the output of a motor for driving a rotary cutting blade is small and also capable of preventing retainment of the material to be cut which has been caught between the adjacent blades or cutting chips remaining without being discharged.

CONSTITUTION: A cutting device is constituted of the following rotary part 3 and a fixed blade 5 arranged near thereto. The rotary part 3 is formed by alternately overlapping a large-diameter rotary cutting blade 1 having a saw- toothed edge whose rear part is cut off and a small-diameter rotary cutting blade 2 having the saw-toothed edge at a plurality of pieces. A warp space Ws is present wherein the tip positions 1a, 2a of the respective rotary cutting blades 1, 2 are stepwise dislocated and the tip thereof is thoroughly absent in the direction of the driving shaft of the rotary cutting blades. In addition thereto, the tips of the respective rotary cutting blades are forward tilted. Furthermore the tip positions 1a, 2a of the respective rotary cutting blades 1, 2 are tilted for the driving shaft 4 thereof.