PURPOSE: To increase rupture life of a band saw blade by way of preventing a wheel bending stress from generating on the band sad blade.

CONSTITUTION: A band saw blade snapping pressure rotation means 13 to drive a band saw blade to run by rotating the endless type band saw blade 9 by way of snapping it and sliding it in contact with it, a rotational drive means 25 to rotationally drive the band saw blade snapping pressure rotation means 13 and a brake means 29 to give a tensile force to give running resistance to the band saw blade 9 by way of snapping the band saw blade 9 at the upstream side of the band saw blade snapping pressure rotation means 13 seen from the running direction of the band saw blade 9 are provided, the band saw blade 9 is directly driven by the band saw blade snapping pressure rotation means 13 without using a wheel, and it is devised that a tensile force is given only between the arrangement position of the band saw blade snapping pressure rotation means 13 and the arrangement position of the brake means 29 to give a tensile force, and cutting of a cut material M is carried out between them.