An illumination apparatus includes: a case having an opening portion; a light source disposed in the case and including a plurality of light-emitting elements; a light diffuser which is disposed in the opening portion, and diffuses and transmits light emitted from the plurality of light-emitting elements; and a controller that controls light emission from the light source. The controller: controls light emission from the plurality of light-emitting elements to project an image on the light diffuser, the image changing with time; and when changing the light emission from the plurality of light-emitting elements changing the image, controls the light emission from the light source to keep a change in at least one of (i) a light amount, (ii) a color temperature, and (iii) a spectral distribution of light emitted from the illumination apparatus within a predetermined range.