The major causes of material aging of storage tanks and vessels is thickness reduction of plates due to unexpected corrosion. And it is extremely difficult to detect such defects or analyze corrosive trend of the whole plates by other inspection systems. On the other hand, it is asked for curtailment of maintenance expense. Such a background is taken into consideration. We were inquired about the method of grasping the status of the background of tank bottom, and shell and vessels' shell and quantitatively with high precision. We have succeeded in development of inspection equipment and system. An advanced High-speed Inspection System has been developed in order to achieve an accurate inspection for corrosive conditions of whole plates of storage tanks and pressure vessels in a shorter period and at a lower cost. The exact identification of the corroded portions of the plates by this system will enable us to evaluate metal loss and to make appropriate partial repair of the defective, which contribute to extreme cost reduction for repair of defective plates comparing with replacing of the whole plates as done in the past.