A thermoelectric generator has a high temperature heat source part provided on a first passage through which a first fluid for cooling an engine flows, a low temperature heat source part provided on a second passage through which a second fluid having a temperature lower than that of the first fluid flows, and a thermoelectric element for producing electric power by a temperature difference produced between the high temperature heat source part and the low temperature heat source part. The first passage is included in a first circuit in which the engine and a first radiator for cooling the first fluid are connected in loop through a main passage. Further, the first passage is in parallel to the first radiator in the first circuit. The second passage is included in a second circuit that is separate from the first circuit and includes a second radiator for cooling the second fluid.