PURPOSE: To improve the condensing heat transfer efficiency as a whole by a method wherein an interval between eliminating plates provided at the lower side of a downward condensing heat transfer surface is specified, then the thickness of a liquid film part formed on the downward condensing heat transfer surface is made to be thin.

CONSTITUTION: Plural eliminating plates 5 are arranged on the lower side of a downward condensing heat transfer surface 1 perpendicular to thereof. By arranging the eliminating plates 5 on the heat transfer surface 1 in such a manner, a part or all of a liquid film 2 falls down along the eliminating plate 5, finally, drops down after changed to a liquid dropping 8. Film 7 shows the liquid film on the eliminating plate 5. The swellings of a liquid film part change to smaller size, therefore, relatively thinner liquid film part 3' is formed between each eliminating plate 5, in result, the heat transfer efficiency is made to be larger. The thickness (t) of the liquid film part 3' is extremely varied based on the interval B between each eliminating plate 5, the moving of the liquid film 3' is also varied extremely. In case of that the wave length of liquid film is (λ), the heat transfer efficiency is extremely increased up to more than two times within the range of (a) (0.3<B/λ<1).