To miniaturize a lens barrel and to stably drive a diaphragm in the case of driving a diaphragm blade by a diaphragm driving part and a driving lever.

This device is equipped with a first driving lever 31 provided on the output shaft of an iris stepping motor 30 supported by a second moving ring 5 holding a part of a lens group, and a second driving lever 32 turnably supported by a rotary shaft 32a at the optimum position of the ring 5, and the top pin 31a of the lever 31 is fit in the long groove 32b of the lever 32, and a driving pin 32c provided on the lever 32 is fit in the long groove 7b of a pair of diaphragm blades 7, and the blade 7 is turned by the driving force of the motor 30 through the levers 31 and 32, so that its stop amount is adjusted.