Disclosed is a display device with improved brightness achieved by increasing electron emission efficiency of a thin film cathode. Phosphors are irradiated with electrons emitted to a vacuum through a flat thin film which is thinner than 5 nm and is disposed so as to face the phosphors. A top electrode for emitting the electrons is formed by stacking thin films of Ir, Pt, and Au, and performing a heat treatment so as to reconstruct the top electrode to have a structure in which thick island parts and a flat thin film part mixedly exist.