PURPOSE: To machine the bevels at both ends of a lengthy material reasonably and efficiently by machining one end face of a work material on a feed conveyor, then feeding the work material to a rear conveyor, and machining the other end face with a machine reversedly faced.

CONSTITUTION: A work material (m) is fed by a feed conveyor C1, the end edge hits the contact piece 26 of a rotary arm 25 for positioning, and it is firmly clamped by vice pieces 14a, 14b and a depressing plate. Then, cutters 50a, 50b are allowed to bite, and necessary route faces and bevel angles are cut. Next, a rotary board 39 is rotated, and bevels are machined on the whole peripheral edge of the material. In addition, cutters 50a, 50b are allowed to escape and a clamp unit is released, a machine A is moved to the position of a reversing unit by a horizontal shifting unit B, and the rear end of the work material (m) fed to a rear conveyor is cut-machined.