A direct lighting unit fits in opposition to an opening of a roof of a vehicle's cabin so as to illuminate a light directly the cabin. An indirect lighting unit is disposed around the outer circumference of the direct lighting unit. The indirect lighting unit contains a plurality of LEDs disposed at fixed intervals so as to emit light outward. The LEDs are controlled to indirectly illuminate the roof. When the direct lighting unit is mounted to the roof, a fixing piece supports a grooved edge portion of the indirect lighting unit so that the indirect lighting unit is immovably held between the fixing piece and the roof. Thus, the direct and indirect lighting units are simultaneously secured to the roof.