WIDTH TENSION GENERATING DEVICE FOR SHEET OF BASE MATERIAL, AND METHOD FOR GENERATING WIDTH TENSION IN SHEET OF BASE MATERIAL

PROBLEM TO BE SOLVED: To provide a width tension generating device for a sheet of base material, and a method for generating width tension in the sheet of base material, capable of effectively correcting waving and wrinkling in the sheet of base material. SOLUTION: A base film 12 is carried at a prescribed carrying speed V1, and for a second guide roll 16, rotation drive to it is controlled in such a way that a circumferential speed V2 of its outer circumferential surface 1602 is lower by a prescribed ratio than the carrying speed V1. Carrying speed to both side parts of the base film 12 pressed by the outer circumferential surface 1602 of the second guide roll 16 and an outer circumferential surface 2006 of a pressure contact part 2004 of an expander roll 20 is set to be lower than the carrying speed to a width center part of the base film 12. Tension is thus generated on the downstream side of the second guide roll 16 and the expander roll 20 in such a direction as to expand the base film 12 from the width center part toward both sides outward.