PURPOSE: To automatically form required bending parts at both ends of a bar by positioning a movable shear which is able to slide in the longitudinal direction of the bar, and by fixing the length of the trailing end of the bar which applies bending to the leading end for a bending device.

CONSTITUTION: A slide block 45 slides with a cylinder-piston operating assembly 39, and a projection 43 touches a positioning member 41 and is held at a required position in relation to a shear 24. The positioning member 41 is moved and positioned by a motor 46 for driving a screw 47 for engaging a sliding probe 49 with a sleeve 48, and the movable shear 24 is positioned within a range determined from minimum and maximum distances from a bending assembly 35. Therefore length of the trailing end (C) of a bar 129 can be varied, after the required bends are applied to the leading end (T), and by providing the trailing end (C) with an abutting pin 44 which can be pulled against the transverse motion of the bar 129 during bending process and by rotating a bending disk 11 having a molding roll 12 and a bending pin 13 of the bending assembly 35 a clockwise or counterclockwise required bending part can be formed.