The section of jointed concrete pavement was constructed on Tokai-Hokuriku Expressway in the central region of Japan main island, which was opened in 1986. After 30 year service, small faulting has begun to appear at many joints. In order to grasp the entire situation of the joints, the FWD tests were performed at all joints in 2011 and 2017, and the structural status of each joints was evaluated from the results of the tests with a backcalculation method developed in this study. In this method, the FWD deflections were simulated with the randomly generated layer elastic moduli using the three dimensional finite element method, considering the degradation process at the joint. A database of FWD deflections, layer elastic moduli and the associated stage was created from the simulation results. The layer moduli were identified from the measured FWD deflections at a joint by searching the closest calculated FWD deflections to those measured from the database. Some of the joints, which were judged to be severely damaged, were excavated to check the actual status of the joint and validate the developed evaluation method. The evaluation on the joints of this particular concrete pavement revealed that the number of degraded joints has been increased rapidly from 2011 to 2017, getting worse in recent years. Also, some backcalculation results imply that many dowels of the joints with the high load transfer efficiency and low deflections are corroded and some of them completely broken, and that some extent of void exists underneath the joint.