The light-emitting display device comprises first and second thin film transistors. The first thin film transistor includes a first gate electrode; a first oxide semiconductor film; and a first electrode and a second electrode which are electrically connected to the first oxide semiconductor film. The second thin film transistor includes a second gate electrode electrically connected to the second electrode; a second oxide semiconductor film; a third electrode; a light-emitting layer and a fourth electrode over the second oxide semiconductor film. A work function of the second oxide semiconductor film is higher than a work function of the fourth electrode.