An organic light emitting display device which can prevent separation of a buffer layer, thereby reducing an electrical short is disclosed. One embodiment of the organic light emitting display device includes a substrate made of a metal, a metal thin film formed on the substrate, a buffer layer formed on the metal thin film, and an organic light emitting diode formed on the buffer layer. Accordingly, a leakage current caused by an electrical short can be effectively prevented by preventing the separation of the buffer layer.