To provide a thermal power device which can efficiently output in a small area by increasing area efficiency of a thermo-element in a thermal power device using the thermo-element for generating power by using temperature difference.

Thermo-electromotive force supplied from a thermo-element device 10 is raised in voltage with a voltage rise part 30 and stored in a condensing part 21. As electro-motive voltage of the thermo-element 10 is set lower by storing the thermo-electromotive force after raising its voltage or supplying it to a processing part 9, semiconductor units for constituting the thermo- elements 10 can be reduced in number. Thereby, area per one semiconductor unit may be increased and area efficiency of the thermo-element device 10 can be improved.