Provided is a flat lamp which includes a lower substrate and an upper substrate arranged to face each other and forming a discharge space between the lower substrate and the upper substrate, a plurality of discharge electrodes formed at at least one of the lower substrate and the upper substrate, a plurality of spacers provided between the lower substrate and the upper substrate to maintain a uniform gap between the lower substrate and the upper substrate, at least one auxiliary electrode provided in each of the spacers, in which a voltage is induced as a voltage is applied to the discharge electrodes, and a fluorescent layer formed on an interior of the discharge space.