A thermoelectric generating unit is configured to generate based on a temperature difference between a cold side and a hot side. A heating part includes a plate-like hollow member and tubular member. The hollow member is provided along a hot-side surface of a thermoelectric transducer, and forms a plate-like cavity inside. The tubular member forms a tubular cavity which communicates the plate-like cavity, with two open ends of the tubular member being positioned distantly from each other and connected to the plate-like hollow member. The tubular member is heated from outside by a hot fluid. The plate-like cavity and the tubular cavity form a circulation path in which a heating medium charged in the cavities circulates.