As viewed from above a straight line Lst that passes through the center of a widthwise direction of a lower end 125a of a through hole 125 and is parallel to an arm turning spindle 123, the center of the widthwise direction of the lower end 125a of the through hole 125 is positioned on one side with a reference of a nip line Ln showing a position where a peripheral surface 131A of a press roll 130A is closest to the peripheral surface 131B of the press roll 130B, at both a central position Pc where the arm member 121 does not swing and at a swinging end Pe where the arm member 121 swings the most.
