This paper deals with the development of an integrated model for rainfall-runoff/flood inundation simulation and economic loss estimation, especially focusing on Sayo Town, Hyogo Prefecture, Japan where there was a severe flood disaster due to a heavy rainfall event on 9-10 August 2009. Firstly, the rainfall over the Sayogawa river catchment at the time is analyzed by using the composite radar and Radar-AMeDAS reanalysis data by the Japan Meteorological Agency in addition to the ground observation data. Second, the rainfall-runoff and flood inundation processes are simulated using the integrated model with the Radar-AMeDAS reanalysis data. The simulated inundation area shows the good agreement with the inundation record. Then, the economic loss estimation based on the simulated inundation area and depth is carried out and compared with the prospected value reported by the municipal government. The house/building economic loss estimated is 20.4 billion Japanese Yen, which agrees well with the reported value 18.5 billion Japanese Yen.