To prevent lowering of a rotational speed of a cutter used for a sawdust production apparatus upon production, eliminate noises, increase the life of the cutter, and improve shaft horsepower of a motor.

This invention aims at elongation of the life of a cutter blade and stable operation of an apparatus by increasing shaft horsepower, by using a helical cutter formed by helically assembling the cutter blade provided with protrusions acting as a key for fitting a cutter, for a drum provided with a plurality of key grooves on a drum circumference to which the cutter blade is mounted for cutting and crushing ends of wood, and by cutting and crushing the wood on the drum circumference with the rotational speed lowered stepwise.