Resins (5, 6) are interposed as insulating layers between heat radiation side and heat absorption side heat exchange bodies (2, 3) and heat radiation side and heat absorption side electrodes (41, 42) of a thermoelectric conversion element module (4). The resin (5) is fusion bonded to the heat radiation side heat exchange body (2), and the resin (6) is fusion bonded to the heat radiation side heat exchange body (3). The material of the resins (5, 6) is, for example, a thermosetting plastic. The thermosetting plastic becomes soft when heated and then cures. At the time of fusion bonding of the resins (5, 6) to the heat exchange bodies (2, 3), the heat exchange bodies (2, 3) and the resins (5, 6) are heated and pressed. Then, the resins (5, 6) become soft and enter the cavities and flaws formed in the surfaces of the heat exchange bodies (2, 3). The resins (5, 6) having entered the cavities and flaws cure to fill the cavities in the surfaces of the heat exchange bodies (2, 3).