PROBLEM TO BE SOLVED: To provide a leukocyte remover of which speed of filtering bloods is lowered little and which does not cause an improper attachment of a housing. SOLUTION: The leukocyte remover 1 is composed of a bag-shaped housing 2 made from a soft resin, filter 5 to remove leukocytes that is settled as it separates the housing 2 into a chamber for flooding bloods and another one for draining bloods, port 6 to be flooded bloods that is set at the one end of the housing 2 and also connects with the chamber for flooding bloods and port 7 for draining bloods that is set at the other end of the housing 2 and also connected with the chamber for draining bloods. The inside wall of the bag- shaped housing made from soft resin that faces the chamber for draining bloods of the filter to remove leukocytes is being uneven as their height differences among each level are 0.2-2 mm.
