Disclosed is an LED lighting device which is easily assembled and disassembled and has a stable assemblability without structural shaking. The LED lighting device is able to improve a heat radiating characteristic and optical efficiency.The LED lighting device comprises a light guide plate comprising a top surface; an upper case comprising a base disposed on the top surface of the light guide plate, and an edge extending from the base, wherein the base is thicker than the edge; a lower case comprising a body coupled to the edge of the upper case; a reflective sheet disposed between the top surface of the light guide plate and the base of the upper case; and a light source unit disposed between the light guide plate and the body of the lower case.