A lighting device comprising: a heat sink including a first heat radiation part and a second heat radiation part; a light source module including a substrate disposed on the first heat radiation part of the heat sink, and a light emitting device disposed on the substrate; and a power supply unit which is disposed within the second heat radiation part of the heat sink and supplies power to the light source module, wherein the second heat radiation part of the heat sink comprises an inner portion receiving the power supply unit therewithin, an outer portion enclosing the inner portion, and a first receiver disposed between the inner portion and the outer portion, wherein the first heat radiation part of the heat sink comprises an upper portion which is disposed on the inner portion of the second heat radiation part and on which the substrate of the light source module is disposed, and a lower portion disposed in the first receiver of the second heat radiation part, characterized in that: the second heat radiation part comprises a connection portion extending from lower portions of the inner portion and the outer portion, the first receiver is a gap formed between the inner portion and the outer portion, and a shape of the gap of the first receiver corresponds to a shape of the lower portion of the first heat radiation part. a heat sink including a first heat radiation part and a second heat radiation part; a light source module including a substrate disposed on the first heat radiation part of the heat sink, and a light emitting device disposed on the substrate; and a power supply unit which is disposed within the second heat radiation part of the heat sink and supplies power to the light source module, wherein the second heat radiation part of the heat sink comprises an inner portion receiving the power supply unit therewithin, an outer portion enclosing the inner portion, and a first receiver disposed between the inner portion and the outer portion, wherein the first heat radiation part of the heat sink comprises an upper portion which is disposed on the inner portion of the second heat radiation part and on which the substrate of the light source module is disposed, and a lower portion disposed in the first receiver of the second heat radiation part, characterized in that: the second heat radiation part comprises a connection portion extending from lower portions of the inner portion and the outer portion, the first receiver is a gap formed between the inner portion and the outer portion, and a shape of the gap of the first receiver corresponds to a shape of the lower portion of the first heat radiation part. wherein the second heat radiation part of the heat sink comprises an inner portion receiving the power supply unit therewithin, an outer portion enclosing the inner portion, and a first receiver disposed between the inner portion and the outer portion, wherein the first heat radiation part of the heat sink comprises an upper portion which is disposed on the inner portion of the second heat radiation part and on which the substrate of the light source module is disposed, and a lower portion disposed in the first receiver of the second heat radiation part, characterized in that: the second heat radiation part comprises a connection portion extending from lower portions of the inner portion and the outer portion, the first receiver is a gap formed between the inner portion and the outer portion, and a shape of the gap of the first receiver corresponds to a shape of the lower portion of the first heat radiation part. the second heat radiation part comprises a connection portion extending from lower portions of the inner portion and the outer portion, the first receiver is a gap formed between the inner portion and the outer portion, and a shape of the gap of the first receiver corresponds to a shape of the lower portion of the first heat radiation part.