The channel deformation in Kinu River during a flood period was investigated in the present study. Field measurement and film analysis were conducted to quantify the temporal and spatial changes in channel profile in the reach of 54.5-56.5 km from the confluence point to Tone River in the term between 2001 and 2003. Considerable amount of bank erosion and channel shift were observed, and the alternative channel was created just after the final flood during this term. As a result of this analysis, it was found that the magnitude of channel deformation depends on an individual flood discharge and also on the history of the former flood events. Numerical analysis was also conducted to understand more deeply the mechanism of this channel deformation. It was confirmed that the numerical model worked fairly well.