Abstract: A light control board comprises a plurality of electrochromic panels which are composed of electrochromic elements and which are situated in one plane. Control means controls the optical transmissivity of each of the electrochromic panels. Thus, the quantity of light passing through the light control board is controlled with resultant illumination control of an empty space. By employing belt-shaped electrochromic panels, it is possible to block or pass the light partially at the surface of the light control board for effective utilization of light according to an intended purpose. Furthermore, by incorporating measurement means into the light control apparatus to detect environmental conditions inside as well as outside, it is also possible to utilize light more efficiently in compliance with changes in surrounding conditions.