To provide a method and a device for condensing a water-soluble organic matter, which can collect a highly concentrated water-soluble organic matter, save energy, and reduce cost of the device by reducing a membrane area. According to the present invention, the permeability ratio of a vapor-permeation separation membrane 5 disposed at least immediately before a final outlet on a non-permeation side in the separation membrane device 52 is lower than those of the other vapor-permeation separation membranes 5 while a hybrid process combining distillation by the distillation column 2 with membrane separation by the separation membrane devices 51 and 52 including a plurality of vapor-permeation separation membranes 5 is used and energy saving performance is maintained. Therefore, a highly concentrated and condensed component of a water-soluble organic matter is obtained. In addition, it is possible to reduce a membrane area of the vapor-permeation separation membranes 5 in the whole separation membrane devices 51 and 52 and to provide a technology leading to reduction in cost of the device.
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