An LED module is disclosed. The LED module includes: light sources elongated in a first direction; a mount supporting the light sources; and a composite reflector integrated with the mount to guide light received from the light sources. The composite reflector includes a first region arranged adjacent to the light sources to reflect light in a second direction substantially orthogonal to the first direction, a third region arranged away from the mount to reflect light in the second direction substantially orthogonal to the first direction, and a second region whose portions overlap the first region and the third region and formed with a plurality of diffraction lines through which light is diffused in the second direction. The diffraction lines formed on the composite reflector diffract incident light and direct the diffracted light toward the light receiving unit.