Abstract: An apparatus and method for transferring a centrifugally separated component in a liquid contained in a flexible bag is disclosed. The apparatus is composed of a centrifugal container for accommodating flexible blood collecting bag filled with blood, and a pushing mechanism for pushing the blood collecting bag. The pushing mechanism is composed of a pair of rollers for pushing a soft material part of the cylindrical portion of the centrifugal container from opposite directions in such a manner that the soft material part is deformed inwardly to project inside the centrifugal container and increase inner pressure of the flexible bag to transfer separated component out of the flexible bag. According to the apparatus and method, the yield for collecting the separated component obtained by centrifugal separation can be increased, and the time required for collection can be decreased.