On August 25, 1825, the Tain-Tournon bridge was open to the public use by Marc Seguin and his four brothers. This is the first wire cable suspension bridge in the world. The purpose of this study is to analyze the process of the foundation works of the bridge on the basis of “notes” and “memoirs” written by Marc Seguin and to evaluate the historical meaning of this bridge works in the context of the innovation of modern suspension bridges. The authors try to reappear several figures of the foundation works like sheet-piles, bridge pier, etc. On the bridge site, innovative works were carried out not only in the superstructure but also in such foundation works as the utilization of hydraulic concrete and reinforced concrete, the fabrication of automatic concrete-mixer etc. It may be concluded that the history of modern suspension bridges begins from the Tain-Tournon bridge.
