Provided are a structure, a planar heater including the same, a heating device including the planar heater, and a method of preparing the structure. The structure includes a metal substrate, an insulating layer disposed on the metal substrate, an electrode layer disposed on the insulating layer, and an electrically conductive layer disposed on the electrode layer, wherein a difference in a coefficient of thermal expansion (CTE) between the metal substrate and the insulating layer is 4 parts per million per degree Kelvin change in temperature (ppm/K) or less.