This lighting unit can control luminance in a plurality of block areas independently, and minimize luminance unevenness caused by discretely arrayed light sources, with a reduced number of parts. The lighting unit comprises: a light guide plate having a first and a second grooves formed therein; a first light source group accommodated in the first groove; and a second light source group accommodated in the second groove; the light guide plate having a first light mixing area, a first light emitting area and a second light mixing area; in the first light mixing area, the thickness of the light guide plate progressively increasing away from the first light source group; in the second light mixing area, the thickness of the light guide plate progressively increasing away from the second light source group; and in the first light emitting area, the light guide plate being flat-plate-like.