PURPOSE: To decrease mechanical operating parts and reduce the capacity and size of a pump, etc., by providing rows of air holes in positions of clamping of the front and rear ends of a sheet on a drum around which the sheet is wound and by sucking air to clamp the sheet and exhausting the air to unclamp the sheet.

CONSTITUTION: When a sheet bite-in claw 23 is open, the ffont end Sa of a sheet collides against a stopper 25 and is revolved together with a drum and thrusted by a handling roller 64. At the same time, the rotation of a pair of send-out rollers 69 is stopped to eliminate the looseness of the sheet. A suction pump is then operated by the action of an solenoid valve to suck the front end of the sheet S first and thereafter suck the bite-in claw 23 and clamp the front end Sa. When the rear end Sb of the sheet is brought to air holes 52 for the rear end, this end is clamped by suction in the same manner. To unclamp the sheet, air is exhausted from the pump. Since the front and rear ends of the sheet are separately clamped and unclamped, the capacity and size of the pump and a noise can be reduced.