This study aims to separate the inclusion through the centrifugal force acting on the inclusion. The results obtained through the water model experiments and numerical calculations shows as follows: (1) The swirling motion works effectively to separate the inclusions. (2) The magnitudes of most affecting factors for pushing the inclusion towards the central area from the wall through the swirling flow are in the order of swirl velocity of balk flow, diameter of inclusion, axial velocity, radius of nozzle and density of inclusion.