The present invention relates to a thin film transistor for easily displaying gradation of an organic electroluminescence display device and a fabrication method of the thin film transistor, and an organic electroluminescence display device using the thin film transistor. The present invention provides an organic electroluminescence display device comprising a thin film transistor; a protection film and an organic light-emitting device electrically connected to the thin film transistor, wherein an S-factor of the thin film transistor is 0.35 V/dec or more.