PURPOSE: To make accurate control over nip pressure performable, by making an arm supporting point and a winding spool center point into horizontality, while setting an interval between both these points and a distance between a fulcrum and rider roll center down to identity, and calculating them in due consideration of the detected value of a tilt angle of an arm.

CONSTITUTION: Nip pressure of a rider roll 4 being supported by two arms 2 in the breadthwise direction of a takeup roll 3 is detected by a nip pressure detector 7 at two spots at both sides, while nip pressure WT1 and WT2 are added by an adder, securing nip pressure WT being slipped to the whole width, and operation takes place with a nip pressure operator, whereby logic nip pressur WNIP is secured and this value is displayed on a nip pressur setting signal WNB with a subtracter, securing deviation operation WO and, after passing a signal reverser, the deviation operation WO is subtracted from maximum nip pressure WN by the subtracter, thus output WP commensurate to the setting nip pressure is secured. Next, after being converted into air pressure by an electro-pneumatic converter, a cylinder unit 1 operates via a select solenoid valve whereby there is produced force F uplifting the arm 2. Therefore, accurate nip pressure control takes place.