PURPOSE: To control accurately plural diaphragms and shutters with a compact, simple and inexpensive configuration.

CONSTITUTION: When a plunger type electromagnet 30 is made to be in a first energized state, a movable iron core 34 is displaced to the right to push a semi-circular boss part 11d by a locking lever releasing end face and a locking lever 11 is turned to the left to release the restraining of a sector lever 7 by a first restraining part 11a and a diaphragm restricting lever 15 by a second restraining part 11b. The sector lever 7 is turned to the right by the energizing force of a spring member 9 to open diaphragm shutter blades 3 and 4 up to a small diaphragm aperture. When the magnet 30 is shifted to a degaussing state, the movable iron core 34 is displaced to the left by the energizing force of a return spring member 19 to drop the sliding projection 15b of the diaphragm restricting lever 15 into a first dropping recess 34h. At this time, the final energization is executed to hold the sliding projection 15d and the turnable amount to the right of the sector lever 7 is spread up to the position of the opening aperture. After the lapse of a specified time, the final degaussing is executed to return the movable iron core 34 to an initial position.