A vaporized solvent emitted from the laundry in the drum during the drying process is condensed within an air passage. From this passage a liquid mixture (solvent and water) is guided to a first liquid storage tank 50 through a liquid mixture line 51. An air relief pipe 52 is connected to an intermediate point of this line so that air coming from the air passage is released through an activated carbon filter 53 to the outside. The outlet end 51a of the liquid mixture line 51 is immersed in the solvent in the upper layer within the first liquid storage tank 50. Due to the hydraulic pressure acting on the outlet end 51a, the air tends to flow toward the air relief pipe 5. This reduces the current pressure of the air coming from the air passage and alleviates its influence within the first liquid storage tank 50, so that a vertical motion of the interface between the solvent and water due to the current pressure is suppressed. Thus, unwanted matter gathering around the interface is prevented from sticking to a filter, and the solvent is prevented from being discharged.