To suitably adjust an individual difference at each step in a diaphragm device constituted to control a plurality of diaphragm apertures having different areas stepwise.

In the diaphragm device, when a diaphragm input means 44 inputs a predetermined diaphragm value, a control circuit 39 rotates motors M1 and M2 for driving diaphragm members 16 and 17 via a motor drive circuit 49 based on information obtained from Hall elements 37 and 31 indirectly detected from rotating positions of rotors 34 and 25, and information obtained from a diaphragm control data storage circuit 40, whereby the predetermined diaphragm aperture is obtained. When adjusting the individual difference after assembling, the motors M1 and M2 are rotated based on reference data stored in the diaphragm control data storage circuit 40 in advance, and output voltages from the Hall elements 37 and 31 obtained when the rotors 34 and 25 stop are compared with a reference voltage in design obtained from voltage reference data 46 by a comparator 42 circuit for adjustment. According to comparison information, adjustment data are extracted from a time table 48 by an adjustment data extraction circuit 43 and stored in the diaphragm control data storage circuit 40.