The elucidation of the developing process of sand bar in the river mouth is important for river management. In this study, in order to clarify the developing process of sand bars in the Yura river mouth located in Fukuchiyama city in Japan, the field measurements of sand bar form were carried out. Numerical simulation were also carried out using a series of two-dimensional model of wave and bed material load. In those results, the numerical results for the developing process of sand bar agree well with the field measurement results, and the developing process of sand bar at the Yura river mouth was evaluated by results of numerical simulation and field measurements.