PURPOSE: To realize manufacture of bags different in specification or in capacity in manufacturing of bags in the state cylinder extending bodies are filled in a long and a series of vinyl sheet cylinder.

CONSTITUTION: A pair of right and left cylinder extending bodies 6, 6 provided with extending flaps 3, 3 to be inserted into a long, continuous and a series sheet cylinder drawing part, and for tensing the cylinder by a spring in the front and back directions by a spring and beam flaps 5 to be tensed by the spring in the width direction are connected by a connecting member 7 so that the space in the width direction may be freely adjusted.