PURPOSE: To easily perform the finishing of washing on the next morning by keeping the humidity conditioning state of cleaned up washing to which washing and humidity conditioning are applied by a continuous washing machine line for a long time at least over one night.

CONSTITUTION: The cleaned up washing 2 to which the washing and dehydration is applied by the continuous washing machine line is housed in a sling bag 4 classified by every kind of washing, and after that, the sling bag 4 is sent to a cleaned up washing stock lane 6 in a dry prevention chamber 16, then, it is stocked transiently. A stocked sling bag 4 is sent to finishing rolls 12-15 corresponding to the progressive status of work. Since the sling bag is stocked in the dry prevention chamber 16, the drying of the cleaned up washing can be prevented from occurring.