PURPOSE: To remove simply the air between film layers by a method wherein a belt substance with contractile force is coiled spirally about the outer circumference of a rolled plastic film and both ends of the belt substance are fixed.

CONSTITUTION: At both ends of the rolled film 1 formed by winding plastic film about the core 3, detachable supports 4 are equipped on the openings of the core 3 and each fixing piece 5 for fixing each belt substance is mounted on the parts of the respective supports 4. The belt substance 2 having a contractile force in the lengthwise direction is wound rotating each support 4 on the external circumference of the said rolled film 1 and at the same time, successively wound spirally from one end side of the said rotating rolled film 1. When both ends of this belt substance 2 are fixed by the above-said fixing pieces 5, the air between the film layers is removed by the contractile force of the belt substance.