An illumination system includes: a light irradiation unit (16) that projects light toward a predetermined illumination area; an image acquisition unit (26) that acquires an image of the illumination area; an object detecting unit (28) that detects a shading object based on image information of the illumination area, acquired by the image acquisition unit; an information generating unit (34) that generates the control information for setting each of the plurality of reflecting mirrors to an on state or an off state such that a plurality of irradiation patterns are alternately irradiated, each of the plurality of irradiation patterns being a pattern in which a shaded area and dark pixels and light pixels around the shaded area are arranged, the shaded area comprising a plurality of dark pixels that shade the shading object, each of the plurality of irradiation patterns having different arrangement of the dark pixels and the light pixels from each other; and an irradiation control unit (36) that controls the light irradiation unit based on the generated control information.