The light-quantity control apparatus includes a base member having an opening allowing light to pass therethrough, a first aperture blade movable in a direction orthogonal to a light passing direction, a second aperture blade rotatable in a surface orthogonal to the light passing direction, and a driving lever to be rotated by a driver to drive the first and second aperture blades. The base member has a protruding portion engaging with a groove portion provided in the first aperture blade, the second aperture blade has a driving cam groove portion with which a driving pin provided in the driving lever slidably engages and a rotation center hole portion with which the protruding portion engages. The second aperture blade is rotated about the protruding portion by sliding of the driving pin with respect to the driving cam groove portion with rotation of the driving lever.