In the eastern marginal area of the Niigata Plain, the Kaj igawa Fault, the Tsukioka Fault and the Muramatsu Fault are distributed. Each fault has a sense discordant with the uplift of the Tide and Echigo Mountains. In order to examine the tectonic features of the active faulting and mountain building, (1) distribution and deformation of river terrace surfaces in the eastern margin of the Niigata Plain, and (2) gradients of river terrace surfaces distributed along the Kaji River and the Agano River, were investigated. The results are summerized as follows. The western part of the Tide and Echigo Mts. has been tilted and uplifted since early Pleistocene, and the middle part has been uniformly uplifted. A large amount of gravel derived frcm the mountains were deposited, forming the ST surface (alluvial fan surface), at the western foot of the mountains. Since the formative period of the ST surface, active reverse faultings have occurred with westerly upthrown sense and left lateral slip. They are presumably the rej uvenations of pre-existing normal fault beneath the Niigata Plain, under compressional field.