In a path audit control method, (1) a unit (a discrete unit or common unit) within a switch holds bitmap information indicating whether each channel identifier is being used to establish a path; (2) a central controller sends the unit bitmap information indicating whether each channel identifier has been used to establish a path; (3) the unit compares bitmap information which it itself is holding with bitmap information that has been sent from the central controller; and (4) if the bitmap information held by the unit and the bitmap information that has been sent from the central controller do not match, the central controller and the unit cooperate to execute matching processing in such a manner that the compared items of bitmap information will be made to match.