PURPOSE: To obtain an aggregate in which the high dimensional precision of a component is not required and which can be assembled in a simple process by a method wherein a ringed thermoelectric element in which a cutout part has been formed is cut into pieces by a hooping stress from the inside.

CONSTITUTION: Many ringed N-type and P-type thermoelectric elements 1, 2 which three or more cutout parts have been formed are prepared alternately. A resin film 11 to which belts by metal foils such as copper foils or the like attached to be stripe-shaped at equal intervals is wound on a heat transfer pipe 8 in such a way that the copper belts are at right angles to an axis and are situated on the outer circumference. The thermoelectric elements 1, 2 are arranged in such a way that one pair of the elements are put respectively on one copper belt. In addition, a resin film 14 which is similar to the resin film 11 is wound on their outer circumference in such a way that the copper belts are situated on the inner circumference and that they are deviated by a half pitch each from the stripe of every copper belt for the resin film 11, and this assembly is housed inside an external heat transfer tube 13. After that, the inside diameter of the internal heat transfer tube 8 is expanded mechanically, a hooping stress is made to act on the thermoelectric elements 1, 2, and they are cut into pieces from the cut parts, and the thermoelectric elements are housed in gaps of a double tube in a state that they have been compression-bonded by a residual stress.