A light control device is provided which (i) controls an arbitrary area on a plane to emit light and (ii) can suppress a crosstalk. A light control device (1) of the present invention includes: a light guide plate (2), having rectangular parallelepiped light guide paths juxtaposed to each other, for guiding light entered an edge of a shorter side of the light guide path, in a longer side direction of the light guide paths; LEDs (3), provided at the respective edges, for emitting lights toward the respective light guide paths; and light-passage amount adjusting means for adjusting ratios of light-passage amount of the light guide plate (2). The light-passage amount adjusting means (i) is provided on a light exit surface side of the light guide plate (2) and (ii) has rectangular parallelepiped switching elements (4) which allow ratios of light-passage amount of the light guide plate (2) to be adjustable. The switching elements (4), juxtaposed to each other in the longer side direction, each extends in a direction perpendicular to the longer side direction.