A thermoelectric generator includes a tube in which a first fluid flows, a power generation module, a holding member, and a heat exchanging fin. The power generation module includes a thermoelectric conversion element. The holding member holds a stacked body in which the power generation module and the tube are stacked with each other such that heat can be transferred between the power generation module and the tube. Both end portions of the holding member are located and fixed outside both ends of the stacked body. The heat exchanging fin includes a pair of end fin portions provided on the reverse surface of the holding member at portions corresponding to the both ends of the stacked body, and an intermediate fin located between the pair of end fin portions and higher in stiffness than the pair of end fin portions.