Abstract: The present invention relates to a tubular membrane separation apparatus used for purification of turbid water, concentration of liquid material, sea-water desalting and so on, which is characterized by a feedwater line, a tubular membrane member adapted to concentrate a feedwater, a concentrated-water line which is disposed in such a manner that the direction of flow therein is opposite to the direction of flow in the feedwater line and a cleaning ball delivery member, said cleaning ball delivery member including a stationary member disposed to cross the feedwater line and concentrated-water line and divide each of the two lines into an upstream and downstream segment, the stationary member being provided with passageways extending in parallel with each other and respectively adapted to communicate the upstream segment of the feedwater line with the downstream segment thereof and the upstream segment of concentrated-water line with the downstream segment thereof, a movable member which comprises at least one