PURPOSE: To permit steadily exchange of heat by a system in which the heating pipe of a multipipe type heat exchanger by which a low-boiling heat medium, e.g., Flon, etc., is heat-exchanged with high-temperature gas, is formed into a double pipe, while a partition plate is inserted inbetween the inner and the outer pipes, and a low-boiling heat medium is used for even a high-temperature gas as heat source.

CONSTITUTION: A partition plate 10 for regulating the flow of heat is inserted inbetween the inner pipe 8 and the outer pipe 9 of a heating pipe 7, and heat to be transmitted through the outer pipe 9 from a high-temperature gas 2 to the inner pipe 8 is regulated by altering the thickness and number of axial partition plates 10a and 10b of the partition plate 10 and also the contact areas of the contacts 10c and 10d between the inner and outer pipes 8 and 9 or by providing a partition portion 10e in the radial direction. Thus, the overheating of low-boiling heat medium flowing in the inner pipe can be prevented, and deterioration entailed can be suppressed, so that a low-boiling heat medium can be used even when high-temperature gas is used as heat source.