PURPOSE: To prevent generation of a film wrinkle so as to stably maintain running of a running film by controlling a running drive motor of the film by a signal of a displacement detector, and connecting a compressed air supply part to a roll-shaped hollow unit through a flexible duct.

CONSTITUTION: A roll-shaped hollow unit 1 is arranged in a pass line between guide rolls 30, 30, fixed to one end of each connecting rod 3, respectively supported to two air cylinders 2, and vertically movably supported, and a film tension fluctuation is performed by a displacement detector 4 provided in a supporting point part of the connecting rod 3, so that a measuring result of the detector is input to a controller 6 to control a drive motor 5 of a rewinding roll 20. Compressed air of fixed pressure, supplied from a compressed air supply part 9 connected through a flexible duct 7, is jetted from an air nozzle of the roll-shaped hollow unit 1, and a space part B is formed between the roll-shaped hollow unit 1 and a running film A to contactlessly arrange the roll-shaped hollow unit 1 with the running film A.