<p>There is provided a twin synchronization method capable of realizing a high-speed and highly accurate operation for a machine having a gantry-shaped structure. The twin synchronization control method synchronizes operation of two motors driving two shafts (movable parts 3) which are mechanically connected by a connection section (connection jig 6). One of the shafts is made to operate at a low speed by position control while the other shaft free-runs following to return to the origin. A position deflection between one shaft and the other shaft is measured by an arbitrary pitch. The position deflection corresponding to the position where one of the shafts runs is recorded as a function in a database. One position instruction is used as a main position instruction which is directly distributed to one of the shafts and which is corrected by using the function recorded in the database to obtain a position instruction to be distributed to the other shaft for operation.</p>
