Provided are a wafer having a thermal circuit and power supplier therefor, which enable the wafer to heat or cool itself without using any additional heating or cooling system. The wafer includes the thermal circuit that is installed on one side of the wafer to be capable of self-heating or self-cooling the wafer in order to perform a heating process or cooling process on a semiconductor device formed on the surface of the wafer and exchanges heat with the semiconductor device. Thus, a temperature of a semiconductor device can be precisely controlled, and heating and cooling energies are greatly reduced through a direct heat exchange method, thus attaining high efficiency. Since the thermal circuit is directly installed in the wafer, it is structurally simple and the costs of production and installation can be notably reduced. Also, the present invention is very advantageous for optimization, miniaturization, simplification, and environmentally friendly production of a wafer heating/cooling system. Furthermore, a temperature measuring circuit is installed on a reverse surface of the wafer so that the amount of energy that acts on an actual semiconductor device or actual temperature can be accurately measured in real time.