PURPOSE: To increase the quantity of a sample to be analyzed without lowering of separation efficiency, by a constitution where a cassette is fitted to the outside circumference part of a rotary material so that the cassette can be fitted and removed freely and many large-diameter and small-diameter cylindrical holes are provided in this cassette in radial directions of the rotary material.

CONSTITUTION: Large-diameter holes 5a and 5b of cassettes 1a and 1b inserted at interval 180°C into insertion holes 13 provided on the outside circumference part of rotary material 12 are constituted in radial directions of rotary material 12. Stationary phase liquid A of a large specific gravity is charged previously in all holes of cassettes 1a and 1b; and when mobile phase liquid B is flowed into one cassette 1a to start countercurrent distribution while rotating and moving rotary material 12, mobile phase liquid B becomes small particles and moves to the side opposite to the action direction of centrifugal force and is filled up in small-diameter holes 6 because centrifugal force acting upon stationary phase liquid A is large, thus performing distribution and separation.