LUMINAIRE

PROBLEM TO BE SOLVED: To suppress deflection of a light guide plate resulting from the light guide plate which moves due to expansion or contraction, and to make illuminance constant.SOLUTION: In an edge light type luminaire which emits light of LEDs 121 and 131 incident from an edge of a light guide plate 11, a light source unit 12 mounted with the LED 121 is fixed on an incident surface 111 of the light guide plate 11 with a screw 15. A light source unit 13 mounted with the LED 131 is fixed on an incident surface 112 of the light guide plate 11 with the screw 15. Thermal expansion of the light guide plate 11 is taken into consideration for the space between the screw 15 and a side surface 142 of a back frame, and the space between the screw 15 and a side surface 143 of the back frame 14. The light guide plate 11 does not receive strong pressure of a back frame 14 by the movement by the thermal expansion, and the deflection can be prevented from occurring. Also, according to the movement of the light guide plate 11, the light source units 12 and 13 also move, and the light guide plate 11 and the light source units 12 and 13 can keep optical positional relationship, so that illuminance can be kept constant.