There is provided a cleaning device capable of preventing a metal wiring layer or the like of an object to be treated, from being oxidized. The cleaning device comprises: a cleaning container 72 having a treating space S having a slightly larger volume than that of an object W to be treated; a fluid storage tank 30 for storing a cleaning fluid 32 for treating the object; supply lines 46A through 46D for supplying the cleaning fluid from the fluid storage tank to the cleaning container; and reflux lines 47A through 47D for returning the cleaning fluid from the cleaning container to the fluid storage tank, wherein the cleaning container, the fluid storage tank, the supply lines and the reflux lines are associated with each other for forming closed cleaning fluid circulating lines 51A through 51D. Thus, it is possible to prevent the metal wiring layer or the like of the object from being oxidized.