Abstract: In a heat exchange system such as an absorption refrigerator, a heat exchange element is disposed in at least one of a heat exchanger, a condenser, an evaporator, an absorber and a low-temperature regenerator. The heat exchange element has a bellows-fin formed into a wave-like shape by consecutively bending a thin plate, and sealing plate sealingly attached onto ends of the bellows-fin, for defining adjacent two chambers alternately in the heat exchanger or the like. The heating fluid and the fluid to be heated are heat-exchanged to each other through the thin plate of the bellows-fin defining respective chambers, so that contact area is increased to thereby extremely improve the heat exchange efficiency. Further, the heat exchange element can be manufactured with ease, to thereby decrease the production cost.