A thermal electron emission backlight device comprises: a first substrate and a second substrate disposed in parallel and separated by a predetermined distance from each other; a first anode electrode and a second anode electrode facing the first anode electrode, the first and second anode electrodes being formed on inner surfaces of the first substrate and the second substrate, respectively; cathode electrodes disposed at predetermined intervals and in parallel with each other between the first substrate and the second substrate; a phosphor layer formed on the second anode electrode; and a plurality of spacers disposed between the first substrate and the second substrate so as to maintain the predetermined distance therebetween. When a predetermined voltage is applied to the cathode electrodes, thermal electrons are emitted from the cathode electrodes.