PURPOSE: To sufficiently cope even with a washing request in a small lot such as an individual unit by providing two or more processing tanks to be independently operated and stopped.

CONSTITUTION: Each solvent 107 is pumped up in a necessary quantity from a solvent tank 106 to be shared through a filter 130 to respective processing tanks 103 and 103a by a pump 120. Next, respective processing tanks 103 and 103a are independently rotated at a low speed. The solvent 107 is circulated in the cycle of the processing tanks 103 and 103a, a button trap 113, a pump 121 and the processing tanks 103 and 103a, and clothes 102 and 102a in the processing tanks 103 and 103a are independently washed. Thereafter, the solvent 107 is discharged from the processing tanks 103 and 103a to a distiller 108. Next, processing drums 104 and 104a are rotated at a low speed, an air is circulated in the directions of arrows 150 and 150a between a recovery air duct part 151 to be shared and the processing tanks 103 and 103a, and the clothes 102 and 102a are independently dried. Thus, the washing processing of the small lot can be sufficiently coped with.