PURPOSE: To eliminate the variance of a blade opening characteristic when a shutter blade is actuated to be opened, to drive the shutter blade in the closing direction thereof even when a time of pulse inputted to a step motor is short to reduce the driving voltage of the shutter and to realize countermeasure to a high-brightness object in accordance with the acceleration of shutter speed at the same time.

CONSTITUTION: The step motor 10 is engaged with a driving member 1 having a cam surface 1a through a gear. A blade opening and closing lever 3 opening and closing the shutter blade 7 through a blade actuating ring 6 is pressed in a direction that the blade 7 is pressed to be opened and locked to the cam surface 1a at an initial position at the same time. The driving member 1 is pressed in the direction of the initial position by a spring 14. When the shutter is actuated to be opened, an effect by the backlash of the gear is eliminated by the pressing force of the spring 14 and the lock releasing time of the lever 3 is stabilized.