To illuminate a direction of maximum illuminance by being deviated from a spot immediately under or over a light-emitting face without degrading characteristics as illumination light.

A light guide plate 8 and a reflecting plate 9 are provided so that the maximum illuminance of light from a light source 4 is on a first region P2 deviated from a spot P1 right under a light-emitting face toward either the front or rear of the light-emitting face. Light from the light guide plate 8 is dispersed by a dispersing plate 6, and a region with the maximum illuminance moves to a second region P3 between the region right under the emission face and the first region. By this constitution, it becomes possible that light distribution characteristics are adjusted so that a spot around a worker's hand may be brightest, or an intended region may be widely illuminated.