PURPOSE: To cur a bar-shaped material, whose external surface provides a rerecessed and a protruded part, without causing the deformation, by providing two edge units, which cross each other from an oppositely facing direction to reliatively approach shearing the bar-shaped material, in a cutting device and forming a surface of the edge unit adapted to the bar-shaped material in a shape along its peripheral shape.

CONSTITUTION: A movable edge 3 and a fixed edge 2, which shear an iron reinforcing bar 1 by shearing action, are arranged in a different position from each other in a longitudinal direction of the iron reinforcing bar 1. A cutting device, vertically moving the movable edge 3 being left as keeping its position for the fixed edge 2 in the longitudinal direction of the iron reinforcing bar 1, shears the bar 1. The cutting device, being constituted such that the edge 2, 3 forms its surface 2', 3' adapted to the iron reinforcing bar 1 in a shape equal to the profile of a spiral crest part 1a and root part 1b of the iron reinforcing bar 1, shears the bar without causing its deformation with the edge eliminating looseness of a movement in the axial core direction.