PURPOSE: To prevent flaw from being generated in a bending processing by providing freely rotatable roll members on a part abutting with a plate stock at the tip of a bending die member in a bending machine.

CONSTITUTION: The plate stock W inserted between an upper die member 20 and a lower die member 21 is bent by the bending die member. While the tip part of the bending die member is abutted, with the surface of the plate stock, the bending die member moves in the vertical and longitudinal directions to perform bending. In this bending the freely rotatable roll members 12 are mounted between the part abutting with the plate stock of the bending die member and the plate stock W. Consequently, in a relative movement, the roll members 12 roll on the plate stock and slip is prevented from being generated between the bending die member and the plate stock W. Thus, ironed flaw can be prevented from generated on the surface of the plate stock W.