To correct the non-contact of film blow-off by a method which is as simple as possible.

When a film is produced from a thermoplastic synthetic resin, the resin is ejected from a blow-off head 1 of an extruder while forming the film blow-off, and the film blow-off acts on a correction device 2 to be corrected to a diameter which can be measured in advance, is placed plainly by a lay flat device, and is taken up. In order to prevent the damage of the surface of the film blow-off, the resin is electrified electrostatically and guided through the correction device 2 which is electrified in the same level before the resin which forms the film blow-off enters the correction device. As a result, the correction of the non-contact of the film blow-off is made possible.