To miniaturize a light quantity adjustment device specially provided with a main light quantity adjustment mechanism and a light quantity sub- adjustment mechanism and to enable the light quantity sub-adjustment mechanism to be driven without causing the unreasonable state of the light quantity adjustment device itself or an optical equipment in terms of constitution.

This device is provided with a light shielding member 4 opened and closed so as to variably set the area of a light passing port and a rotary member 2 which is rotated around an optical axis and which drives the light shielding member 4 so as to open and close it. Then, the optical equipment including a movable member 25 which can be moved in an optical axis direction is provided with this device. Besides, the rotary member 2 is provided with a cam part 2a formed to be extended in the optical axis direction and engaged with a cam follower 15b arranged at the movable member 15 so as to convert the movement of the follower 15b in the optical axis direction to the rotation of the rotary member 2.