A field emission device (FED) includes a top substrate having an anode electrode and a phosphor layer, a lower substrate, at least one cathode electrode having an opening-pattern with at least one opening, an insulating layer located on the cathode electrode, a gate layer located on the insulating layer, and an electron emitter located in the opening of the cathode electrode. The electron emitter is adjacent to the cathode electrode and is electrically connected therewith. The cathode electrode having the opening-pattern is located on a bottom panel. Through the structure illustrated above, uniformity of emitting electron density can be improved and brightness and contrast of color for the FED can be enhanced.