PURPOSE: To provide an apparatus and method for simultaneously carry out bends of a bundle of bars having prescribed diameters or below with good accuracy.

CONSTITUTION: The bars 13 are superposed one on another within a plane nearly perpendicular to a workpiece platform. A bending machine 10 includes a bending unit 14 including an abutment roll 17 and a bending pin 16, a retaining and clamping means 18, and a unit 11 including a gripper 12 for the controlled lengthwise displacement of the bundle 13 of the bars. The retaining and clamping means 18 is partly downwardly retracted during the steps of displacement of the bundles 13 of the bars so as to provide a partial opening which enables the bundles 13 of the bars having the diameter below about 32 mm to slide and be guided. The gripper 12 is partially opened during at least one step of bending cycles in order to maintain the bundles of the bars in nearly a perpendicular position.