PURPOSE: To improve the plate width accuracy and camber correction of a rolled stock by controlling the edger rolling reduction at a work side and driving side taking into consideration the return amt. at the horizontal rolling time from measured plate width and camber value and controlling the observed value by correcting it further.

CONSTITUTION: The shape is recognized by a plane shape calculating device 8 from measured plate width and camber value by a width/camder meter 6, the edging amounts 9, 10 at work side and driving side are decided as well by considering an instructed rolling dimension 7 and considering further the return amt. by a horizontal mill 1, and an edging is executed by actuating the respective edger 2 by control devices 11, 12. In that case, a correction is added on the control devices 11, 12 by detecting actual edging amt. by an edge detecting device 4 before and behind the edger 2. With the edging added with this return amt. the plate width accuracy of a rolled stock 3 is improved, the camber correction is bettered and the yield of the rolled stock 3 is improved.