PURPOSE: To prevent the existence of a cavity in which a diallysis liquid, etc., remain by fixing a housing to a centrifuge, centrifuging the housing, injecting potting material for forming a partition from a fluid port, and stopping the injection when the potting, the thickness of which is increased, leaks from an opened hole.

CONSTITUTION: After a hollow yarn bundle 6a is housed in a cylindrical housing 2, an edge opening at a side for which one partition of this housing 2, for example, a partition 8, is to be formed in sealed with a split cup 26, and this housing 2 is fixed onto a table 22 so that the side of the housing 2 for which the partition 8 is to be formed can be an outside. Next, a drive motor is driven, the table 22 is rotated, the housing 2 is centrifuged, a potting material 25 is injected from a blood introducing port 10 into the housing 2, and the potting material 25 is moved to the edge part side of the housing 2 using centrifugal force. Further, when the potting material, the thickness of which is increased because of the continuation of the injection, reaches the blood introducing port 10, the injection of the potting material is stopped, after that, the potting material 25 is hardened until the potting material loses its fludity, and the driving of the centrifuge is stopped.