The construction of timber truss pedestrian bridge with steel ball joint is a little in Japan, and the investigation on structural performance and influence to deterioration by passage years is none at all. Therefore, soundness and actual condition by the soundness inspection and the dynamic field tests in 2013 and 2014, and structural analysis were conducted to the subjected bridges, and then the structural characteristics by passage year, the vibration serviceability and the actual condition of soundness were investigated. As the results, it is obtained the observation that the dynamic characteristics are changing by pass of 17 and 18 years and the structural rigidity of the both objected bridges are decreasing about 30%.
