PURPOSE: To provide high accuracy line speed control in a film production line or the like by giving direct speed correction to a movable roll according to differential value with respect to variation of pass amount of a conveyer between rolls due to displacement of the movable roll between rolls.

CONSTITUTION: The position of a movable roll 4 is detected by a porition detector 9 to apply speed correction amount 13 to a drive system of movable rolls 4, 6 to perform direct speed correction without varying line speed of conveyers 1, 2, 7 for preventing articles to be conveyed from irregularities of quality. The speed of the delivery side conveyer 7 in the movement of the movable rolls 4, 6 is the sum of the circumferential speed of the rolls 4, 6 converted from the movement distance and the speed of the conveyer 1 so that the direct speed correction is carried out by a correction amount 13 corresponding to the circumferential speed. Also, when the moving speed of the movable roll is low and regular, differential value with respect to variation of pass amount of conveyer 2 between rolls is added to or subtracted from reference speed value of the movable rolls 4, 6 every short time of sampling time so that the speed control can be carried out within the allowable region of extension and loosening.