PROBLEM TO BE SOLVED: To improve performance not only in cleaning a filter and a concentrator, but also in recovering useful substances.SOLUTION: An ascites filtration concentration system includes: an undiluted solution storage container 100 for storing an undiluted solution containing a cell component a filter 1 capable of separating the cell component in the undiluted solution a concentrator 2 capable of separating the solution into a concentrated liquid and a waste liquid a concentrated liquid recovery container 102 for recovering the concentrated liquid a cleaning liquid storage container 103 for storing a cleaning liquid to clean the filter 1 and the concentrator 2 an undiluted solution supply passage 10 that connects the undiluted solution storage container 100 and the filter 1 a filtrate passage 11 that connects the filter 1 and the concentrator 2 a concentrated liquid recovery passage 12 that connects the concentrator 2 and the concentrated liquid recovery container 102 a waste liquid passage 13 connected to the concentrator 2 a cleaning liquid supply passage 14 that connects the cleaning liquid storage container 103 to the concentrator 2 recovery flow rate control means 32 for controlling a flow rate of the concentrated liquid recovery passage 12 waste liquid flow rate control means 33 for controlling a flow rate of the waste liquid passage 13 and cleaning liquid flow rate control means 34 for controlling a flow rate of the cleaning liquid supply passage 14.