An adjusting unit disposed between a housing including at least one or more semiconductor optical devices and a case accommodating an SMPS, so as to adjust the height of the casing. At least one or more light emitting modules are mounted on the bottom surface of the housing, and a position determining unit is disposed in the housing in correspondence to an edge of the light emitting module. A heat sink unit is provided in correspondence to the top surface of the housing. Therefore, transport costs can be significantly reduced by securing the loading space. The semiconductor optical devices serving as a light source can be appropriately arranged, and the semiconductor optical devices can be mounted at accurate positions. Furthermore, products can be rapidly mass-produced due to a simplified manufacturing process thereof.