The bridge which is one of the large span structures is essential to social infrastructures for our recent life styles. However, the deterioration or collapse would happen under service conditions. Such a damage of the bridges would affect not only on economic activities but also our lives. By considering the social impact, maintenance of existing bridges should be planned carefully and their repairs should be executed immediately as soon as possible when the severe problems were observed. Therefore, predicting the current conditions of the bridge is valuable for repairing bridges and it also could bring reduction for amount of the field investigations. So, this system stored survey results and environment information surrounding the bridges. And the system can reason the deterioration of bridges based on Neural Network. In short, the system can identify the bridge that is being degraded.