NOVELTY - The apparatus has a low-temperature unit (130) comprising a heat transfer plate (134) extending from a pipe holder and located opposite to a corresponding high-temperature unit (120). A coolant pipe holder is formed at a side of the heat transfer plate, and supports a coolant pipe (135). A thermoelectric module (140) is placed between high and low temperature units and formed by joining a P-type and N-type semiconductors, and generates electricity using thermoelectric phenomenon caused by a temperature difference between the high and low temperature units.    USE - Thermoelectric generator apparatus for generating electricity in an exhaust gas system of a vehicle e.g. automobile, spaceship and nuclear-powered submarine.    ADVANTAGE - The apparatus ensures that the temperature difference arises at the ends of multitude of the thermoelectric modules and inside the multitude of thermoelectric modules including the semiconductors using the thermoelectric phenomenon so as to generate electricity, so that the generated electricity can charge the vehicle's batteries electrically connected with the multitude of the thermoelectric modules using the vehicle's exhaust gas, thus generating electricity in an effective manner, and hence improving fuel efficiency. The apparatus ensures that a heat exchange mesh is installed between the high-temperature unit and the thermoelectric modules, so that a contact area between the high-temperature unit and the thermoelectric module is large, and a side of the multitude of the thermoelectric modules can be cooled down quickly by the low-temperature unit, thus reducing noise of the exhaust gas passing through the thermoelectric modules, and hence improving efficiency and enhancing design of the apparatus in a simple manner.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross sectional view of a thermoelectric generator apparatus of a vehicle.    High-temperature unit (120)    Low-temperature unit (130)    Heat transfer plate (134)    Coolant pipe (135)    Thermoelectric module (140)