An illumination apparatus illuminating an objective illumination region comprises a plurality of illuminants having light-emitting surfaces radiating diffused light, an illuminant substrate in which the illuminants are disposed so as to be set in array on the circumference, at least one optical member configured to guide the diffused light to the objective illumination region, a movable section configured to drive the optical member so as to be rotatable around the center of the circumference serving as a rotation center, and a lighting control section configured to control a light-emitting timing of the plurality of illuminants. The movable section and the lighting control section operate together such that the quantity of light per unit time of the diffused light guided to the objective illumination region is within a predetermined range.