PURPOSE: To automate a work to remove burrs by a method wherein a disc sander having a balance weight and rockably supported to the chamfering part of a steel plate in a manner to make profile contact with the chamfering part are arranged in a longitudinal direction.

CONSTITUTION: A disc sander to be chamfered is brought into pressure contact with the cut end surface of a steel plate by a profile contact system and is caused to follow waviness and the uneven surface of the cut end surface of the steel plate. Besides, a pressure contact force is regulated by means of a balance weight, and rough chamfering is automatically effected with high efficiency by profile grinding by means of a rigid grinding stone. A belt sander 59 by which finish chamfering is effected softly and resiliently grinds the cut end surface of the steel plate after chamfering. In this case, since a polishing position is set to a free running part 84 between guide pulleys 77 and 78, secondary production of burrs is prevented.