Abstract: A cold cathode fluorescent flat lamp comprising a first plate, a second plate, a fluorescent substance, a discharge gas and a plurality of electrodes is provided. The first plate has a plurality of grooves. The second plate is disposed on the first plate on which the grooves form airtight chambers. The fluorescent substance is disposed on the inner wall of the airtight chambers; the discharge gas is disposed in the airtight chambers; and the electrodes are disposed on both sides of various airtight chambers. Therefore, by disposing the grooves on the inner surface of the first plate, the second plate can dispose on the first plate directly. Furthermore, the second plate disposing on the first plate directly can enhance the strength of the cold cathode fluorescent flat lamp without using rods and spacers.