PURPOSE: To recover the latent heat of vapor effectively and improve operating efficiency by a method wherein the title device is provided with a compressor, compressing steam generated in a reproducer to increase the temperature of the same, and a reproducer heat exchanger, effecting heat exchange between the steam from the compressor and the absorbing liquid of the reproducer, while water, coming through the reproducer heat exchanger, is conducted into a condenser.

CONSTITUTION: A compressor 29 is provided on the passage 23 of steam from a reproducer 19 to compress the steam and increase the temperature of the same and the steam, whose temperature is increased, is conducted through a reproducer heat exchanger 30 provided so as to be dipped into the absorbing liquid 10 of the reproducer 19 to effect heat exchange between the steam and reproduced liquid 10 while water, coming from the reproducer heat exchanger 30, is conducted into a condenser 24 through a pressure reducing and water releasing device 31. The heat of the steam, whose temperature is increased, is released into the absorbing liquid 10 in the reproducer 19 to increase the temperature of the absorbing liquid 10 and condense the same while the steam is condensed to release the latent heat of condensation whereby the latent heat of steam is recovered effectively and operating efficiency can be improved.