NOVELTY - The generator (17) has an open or close valve (40) that is provided at an exhaust pipe (11) and configured to adjust a flow rate of the exhaust gas flowing through a heat receiving passage (23) by adjusting an opening degree of a bypass passage (25). A controller configures to adjust an opening degree of the valve such that the flow rate of the exhaust gas flowing through the heat receiving passage reduces on the condition that the operation mode is selected by the selecting device after completion of warm-up of the engine.    USE - Thermoelectric generator mounted on internal combustion engine such as four-cycle petrol engine for vehicle such as hybrid vehicle and automobile.    ADVANTAGE - The controller adjusts the opening degree of the regulating valve such that the flow rate of the exhaust gas flowing through the second exhaust passage reduces when the second operation mode in which the torque of the internal combustion engine is increased after completion of warm-up of the internal combustion engine, so it is possible to increase the flow rate of the exhaust gas flowing through the first exhaust passage by increasing the opening degree of the first exhaust passage. Thus, an increase in the back pressure of the internal combustion engine is prevented, the decrease in the output performance of the internal combustion engine is suppressed, the amount of heat of the exhaust gas is increased and the power generation efficiency of the conversion module is improved. The heat exchange between the exhaust gas and the cooling medium is facilitated by the controller, so it is possible to achieve early warm-up of the internal combustion engine. The first exhaust pipe, the second exhaust pipe and the cooling pipe are provided coaxially with one another, so it is possible to reduce the size of the thermoelectric generator and also possible to improve the vehicle mountability of the thermoelectric generator.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the thermoelectric generator.    Exhaust pipe (11)    Thermoelectric generator (17)    Heat receiving passage (23)    Bypass passage (25)    Open or close valve (40)