An image data processing system has been developed in order to analyze auroral conjugacy of auroral positions, shapes and motions. The new system has the following advantages : 1) A large amount of image data can be quickly and efficiently analyzed by using the system. 2) The geomagnetic coordinate display and auroral dynamic display produced by the system are useful for comparison of auroral positions, shapes and motions between two hemispheres. 3) The smooth combination techniques of auroral image data make it possible to investigate auroral conjugacy with wider field of view than that of one station. The developed processing system is applied to conjugate auroral TV camera data of September 9-10,1991 events observed at Syowa and Asuka stations, in Antarctica and Husafell in Iceland.