The present invention provides a steam generator capable of greatly improving energy efficiency, and an energy supply system that uses the steam generator. The steam generator of the present invention includes a high-temperature chamber to which heat of 250° C. to 800° C. is supplied; a low-temperature chamber arranged adjacent to the high-temperature chamber and configured to produce low-temperature steam of 50° C. to 185° C. from water using the heat of the high-temperature chamber; and at least one thermoelectric element arranged between the high-temperature chamber and the low-temperature chamber.