A lighting device comprising: a heat sink having an optical transmittance; a light source module including a substrate disposed on the heat sink and a light emitting device disposed on the substrate; and a cover (100, 100') which is disposed on the light source module and outwardly emits a part of light from the light source module, wherein the cover (100, 100') has an inner surface which reflects a part of light from the light emitting device, and wherein the heat sink receives the light from the inner surface of the cover (100, 100') and outwardly emits a part of the received light, characterized in that the cover includes a first cover part disposed on the substrate, and a second cover part connected to an outer circumference of the first cover part, and wherein an optical reflectance of the first cover part is greater than an optical reflectance of the second cover part, wherein the heat sink comprises: a first heat radiation part including an upper portion on which the light source module is disposed, a lower portion connected to the upper portion, and a receiver; and a second heat radiation part including an inner portion which is disposed in the receiver of the first heat radiation part, and an outer portion which encloses the lower portion of the first heat radiation part, wherein the second heat radiation part has the optical transmittance. a heat sink having an optical transmittance; a light source module including a substrate disposed on the heat sink and a light emitting device disposed on the substrate; and a cover (100, 100') which is disposed on the light source module and outwardly emits a part of light from the light source module, wherein the cover (100, 100') has an inner surface which reflects a part of light from the light emitting device, and wherein the heat sink receives the light from the inner surface of the cover (100, 100') and outwardly emits a part of the received light, characterized in that the cover includes a first cover part disposed on the substrate, and a second cover part connected to an outer circumference of the first cover part, and wherein the cover (100, 100') has an inner surface which reflects a part of light from the light emitting device, and wherein the heat sink receives the light from the inner surface of the cover (100, 100') and outwardly emits a part of the received light, characterized in that the cover includes a first cover part disposed on the substrate, and a second cover part connected to an outer circumference of the first cover part, and wherein an optical reflectance of the first cover part is greater than an optical reflectance of the second cover part, wherein the heat sink comprises: a first heat radiation part including an upper portion on which the light source module is disposed, a lower portion connected to the upper portion, and a receiver; and a second heat radiation part including an inner portion which is disposed in the receiver of the first heat radiation part, and an outer portion which encloses the lower portion of the first heat radiation part, a first heat radiation part including an upper portion on which the light source module is disposed, a lower portion connected to the upper portion, and a receiver; and a second heat radiation part including an inner portion which is disposed in the receiver of the first heat radiation part, and an outer portion which encloses the lower portion of the first heat radiation part, wherein the second heat radiation part has the optical transmittance.