An illumination unit includes one or more light sources each including a solid-state light-emitting device having a light emission region configured of one or more light-emission spots, one or more traveling-direction angle conversion device each converting a traveling-direction-angle of light, and an integrator including a first fly-eye lens having cells which receive light from the traveling-direction angle conversion device and a second fly-eye lens having cells which receive light from the first fly-eye lens, the integrator uniformalizing illumination distribution in a predetermined illumination area. An optical system configured with the traveling-direction angle conversion device and the first and second fly-eye lenses has an optical magnification which allows each of light source images to have a size not exceeding a size of the cell in the second fly-eye lens, the light source images being formed on the second fly-eye lens by the respective cells in the first fly-eye lens.