There is provided a lighting device excellent in mass productivity and capable of significantly reducing a production cost and allowing easy provision of a light-weight and large-size lighting device as well as improving a degree of freedom in choosing materials and exhibiting an adequate heat dissipation effect. A heat dissipation portion is obtained by press-working a metal plate. For example, the heat dissipation portion is configured by press-deforming the metal plate into a substantially dome-like shape having a vertically extending peak portion and a vertically extending valley portion that are peripherally and consecutively formed, by repeatedly bending the metal plate along a circumferential direction into a wave shape and concurrently warping the metal plate in an axial direction such that the outer peripheral side of the metal plate is positioned closer to the tip in the axial direction than the central side thereof.