The lighting module includes: a case including an opening from which light is emitted, a base portion corresponding to the opening, and a seat on at least one side of the base portion; a light source unit disposed on the seat; a light guide plate placed within the case and optically connected with the light source unit; and a diffusing plate placed within the case and placed below the light guide plate, wherein the lighting source unit includes a substrate, a plurality of light emitting diodes (LEDs) disposed on the substrate, and a sub-reflector which is disposed on the substrate and covers the plurality of the LEDs, and wherein at least 90% of the light emitted from the LEDs is directly irradiated onto the light guide plate.