PURPOSE: To cut off a workpiece at a high speed to greatly heighten the efficiency of cutting-off, by using a pair of circular saws to cut the workpiece by half, respectively, to completely cut it off.

CONSTITUTION: The rear frame 1a of a machine body 1 covering the moving passage of a workpiece A to be cut off is fitted with crankshafts 2a, 2b which extend over and under the moving passage of the workpiece A and are located in a front and a rear positions in the moving direction of the workpiece A. Each of circular saws 20a, 20b is integrally secured on one end of each of rotary shafts 19 in cylinders 18. The circular saws 20a, 20b are located over and under the moving passage of the workpiece A. The saw 20a carves into the workpiece A at the bottom dead center of the circular locus 21 of the saw 20a to cut workpiece A by more than half. The saw 20b carves into the workpiece A at the top dead center of the circular locus 21 of the saw 20b to cut the workpiece A by more than half. The workpiece A is thus completely cut off at a high speed by the cooperation of the saws 20a, 20b. Therefore, the efficiency of cutting-off is greatly heightened.