Disclosed herein is a plane heater that generates heat by using graphene or the like as the conductive heat generation material thereof. The plane heater includes: a nonconductor substrate; a heat generation material applied to the nonconductor substrate; and a pair of electrodes configured to generate resistance heat in the heat generation material. The pair of electrodes include a first electrode configured to be connected to one pole of a power source, and a second electrode configured to be connected to the other pole of the power source. The sectional areas of at least some portions of the first electrode and the second electrode are determined such that a plurality of electric circuits formed by the first electrode, the heat generation material, and the second electrode can have the theoretically same resistance.