Provided is a plasma flat lamp. The provided lamp includes a discharge gas filled in a discharge area of a discharge container, at least two electrodes generating a gas discharge in the discharge area, a low work function material layer located in a discharge path between the electrodes and collided against gas ions that are generated by the gas discharge, and a fluorescent layer generating visible rays by ultraviolet rays that are generated by the gas discharge in the discharge container. The provided plasma flat lamp reduces a driving voltage due to the low work function material layer against which ions are collided, and increases luminescent efficiency by reducing the absorption of ultraviolet rays of the low work function material layer.