To uniform a moisture percentage of woven fabric after dehydration by considering the problems of conventional technology.

The apparatus is equipped with a suction tube that is arranged between frames of a loom and has a suction opening to be brought into contact with a woven fabric, a steam separator, an aspirator, a first connecting pipe connected from the end part of the opposite side of the yarn-feeding part of the suction tube to a common steam separator, a second connecting pipe connected from the end part of the yarn-feeding part of the suction tube to the common steam separator and a third connecting pipe for connecting the steam separator to the aspirator. The pressure drop of the first connecting pipe is equal to or lower than that of the second connecting pipe.