Generally, in a bending machine such as a press brake or the like, when a workpiece W is subjected to a bending process, for example, when a product of a shape such as shown in FIG. 1 is obtained, first a 90??? bending process is carried out at a bending point 2, then the workpiece W is rotated from top to bottom and the same 90??? bending process is performed at a bending point 1.