PURPOSE: To remove only the fins is conformity wit the shape of cores without damaging the cores by disposing plural pulleys zigzag, putting and tensing wires between the pulleys, and making use of the tension and bending deformation of the wires.

CONSTITUTION: When a pallet placed thereon with cores WW is positioned right under the deburring device, the deburring device moves downward and arrives at the lowermost end position. As a moving plate moves backward, wires 37, 38 contact with the finned parts of the cores WW and bend and deform said parts to a V shape and an inverted V shape. When the entire part of the deburring device is moved upward while this state is maintained, the fins produced in the side edge parts of the cores WW are chipped off from below to above by means of the wires 37, 38 which contact with the fins. When the deburring device arrives at the uppermost end position, the moving plate returns to the original position and the wires 37, 38 restore the original state as well.