To make products which are soft, are optimum for domestic animals and is usable as a fertilizer as well after use by crushing waste wood which products the mats for the domestic animal with a sawdust crusher.

The sawdust crusher rotates at a high speed of 2,000 revolutions per minute and therefore wind is generated by revolving rollers. Raw material (waste wood 3 cm×3 cm) is sucked by the amount necessary to the force of the wind by a hopper 1 installed alongside the revolving rollers and is mixed with the wind. The waste wood is crushed by long and short hammers which are rotated by the centrifugal force. The crushed waste wood is discharged through a screen by the force of the wind and is dashed against a bed plate, by which the waste wood is softened to the sawdust. The sawdust is discharged by a conveyor 12.