To provide a method capable of precisely identifying an exciting force in an actual working period, even in the case a vibration exciter can not be mounted on a point on which the exciting force acts in the actual working period.

The method for identifying the exciting force comprises; a procedure 1 of measuring a vibration response at a response measurement point, when the exciting force caused by a movable part acts on a structure (15) in the actual working period; a procedure 2 of measuring the vibration response at a response measurement point including the above measurement point, when mounting the vibration exciter on the structure from which the movable part is removed, and when bringing a previously known exciting force to act thereon by using the vibration exciter, and then obtaining a vibration transfer characteristic from the point on which the exciting force caused by the movable part acts, up to a vibration response point, based on data of the measured vibration response and the previously known exciting force; and a procedure 3 of estimating the exciting force acting thereon caused by the movable part in the actual working period, based on data of the vibration response measured by the procedure 1 and the inverse matrix of the vibration transfer characteristic obtained by the procedure 2. At least one position on which the vibration exciter is mounted, is an arbitrary position on which the exciting force caused by the movable part does not act in the actual working period.