To decrease the horizontal image position errors by preparing such a constitution, where a 1st guide element support one of both longitudinal edges of a film at least at two points and two rolls of a rocker that is supported by a 2nd guide element set opposite to the 1st guide element, via a spring support the other longitudinal edge of the film.

A 2nd guide element 12 is placed opposite to a 1st guide element 11 with a concentric space secured between them. The element 12 consists of a cylindrical part 14, having a compression spring 15 which functions in the edge direction of a film, and a rocket 16 is rockably supported at the edge of the part 14 set toward the film. The rolls 17 and 18 are rotatably fixed at both ends of the rocker 16 and press the edges of the film by the force of the spring 15. Thus, the irregularities of the film is uniformized, and accordingly the horizontal position errors of images can be decreased.