An electron emission device is provided. The electron emission device includes first and second substrates facing each other, a cathode electrode arranged on the first substrate, at least one opening electron emission region arranged on the cathode electrode, an insulation layer arranged on the cathode electrode and provided with at least one opening corresponding to the at least one opening electron emission region, and a gate electrode arranged on the insulation layer and provided with at least one opening corresponding to the at least one electron emission region. A width H1 of the at least one opening of the insulation layer is equal to or greater than twice a thickness T1 of the insulation layer.