An electron emission type backlight unit which may include a front substrate and a rear substrate, a gate electrode, an insulating unit disposed on the gate electrode, a cathode disposed on the insulating unit that intersects the gate electrode, a first opening formed in the cathode to expose the gate electrode, a second opening formed in the insulating unit to expose the gate electrode, in which the second opening connects to the first opening, an electron emitting unit disposed on the cathode that exposes the gate electrode, in which the electron emitting unit is formed to trace along a boundary of the cathode that defines the first opening, an auxiliary gate electrode disposed on the gate electrode, in which the auxiliary gate electrode passes through the first opening and the second opening; and an anode and a light emitting unit.