An illumination apparatus includes; a first solid-state light source, a second solid-state light source, a first arrangement member provided with a first arrangement surface, a second arrangement member provided with a second arrangement surface, an optical unit configured to reduce a dispersion angle of a light beam. The first solid-state light source emits a light beam having a first directivity. The second solid-state light source emits a light beam having a second directivity greater than the first directivity. A distance from the second arrangement surface to the second light-entering surface is longer than a distance from the first arrangement surface to the first light-entering surface.