PURPOSE: To use an electronic still video camera and to perform accurate exposure control by driving a mobile member provided with plural fixed stops by a driving mechanism to set a preliminarily determinate fixed stop on the optical axis.

CONSTITUTION: The luminance of an object is measured by a light measuring device, and a CPU sends a control signal to a motor 7 to rotate it after determining an optimum stop by operation. The rotating force of the motor 7 is transmitted to a gear 3 through gears 6, 5, and 4, and a rack 2 engaged with the gear 3 is linearly moved to move a mobile member 1 interlocking with this rack 2 in the direction of an arrow. Then, the operation is stopped with a prescribed fixed stop set on the optical axis Z. Thus, an electronic still video camera is used to perform accurate exposure control.