PURPOSE: To generate a large current and to enhance a cooling efficiency by laminating an intervening part containing the same metal as that of a cooling part made of metal between an insulating part and the cooling part.

CONSTITUTION: A thin plate 4 made of aluminum laminated through solder 2 and a nickel-plated layer 3 is interposed in a water cooled tube l made of aluminum. As a result that thermal expansions of the tube 1 and the plate 4 become the same due to heat to be transferred by thermoelectric generating element pieces 11a, 11b by the plate 4, its warpage is eliminated. Accordingly, a connecting strength of an AlN board 6 to the tube 1 is improved to improve capacity of the tube 1 to cool electrodes 8, 8 connected to the pieces 11a, 11b through the board 6. Further, generating efficiencies of the elements 8, 11a, 14, 11b, 8 are enhanced. That is, a current generated between the electrodes 8 and 8 connected to the elements 11a, 11b is increased.