To suppress fluttering of a movable member which moves by rotation of a rotating shaft member while gaining a yoke volume of a coil disposed on a base plate, thereby performing stable drive.

A light adjusting device has the base plate in which an aperture is formed; at least one light adjusting member which adjusts light entering through the aperture; and at least one electromagnetic driving source which operates the light adjusting member. The light adjusting member is provided with the rotating shaft member having magnetism. In the light adjusting device, the light entering through the aperture is adjusted by rotating the rotating shaft member using the electromagnetic driving source and by moving the light adjusting member reciprocally to a first static position retracted from the aperture and a second static position overlapped with the aperture. The electromagnetic driving source includes a yoke and a winding coil wound on the yoke. The electromagnetic driving source is disposed on the base plate such that ends of the yoke are opposed to the rotating shaft member near the constraint point which specifies a position of the rotating shaft member, regardless of a winding number of the winding coil.