A voraxial separation system having an auxiliary filter is disclosed for separating flowable composite media into components. Protruding portions are formed on the base parts of the columnar connecting parts inserted and fitted in the holes in both sides of the opening, and the protruding portions engage with the holes from the rear face sides in the state of the columnar connecting parts having been inserted in the holes completely. A leg engagement mechanism is pivotally connected to the board body positioned generally along the rear section half.