PURPOSE: To improve the use efficiency of a space when a controller is integrated in a lens by separating a driving drum from a motor which is the rotating power source of the driving drum and arranging them so that the respective rotary shafts are intersected orthogonally with each other.

CONSTITUTION: Two stop aperture parts 5a and 5a' are provided on a sheet for adjusting exposure 5. They are folded back and wound to the drum for driving 4 under a tension state so that they are superposed on the optical axis of the lens. By rotating and driving the drum 4 with the aid of the driving motor 1 and moving the stop aperture parts 5a and 5a' in a mutually opposite direction, the diameter of the stop aperture can be changed. The motor 1 is arranged so that the rotary shaft thereof is almost perpendicular to the rotary shaft of the drum 4. Besides, it is arranged in the vicinity of the outside of the width edge of the traveling direction of the sheet 5. Thus, respective parts can be arranged in well balance. Besides, only by exchanging the drum 4, the traveling speed of the sheet 5 can be changed.