At 17 sites, the distribution of frogs was investigated by hearing the croaking. The survey was conducted twice in May 21 and June 25, 2018. Changes in farmland management during the non-irrigation season were investigated by visually interpreting ortho mosaic imagery acquired by UAV (Unmanned Aerial Vehicles). Buffers with a radius of 150 m from 17 sites were created. For each category of farmland management, we analyzed the relationship between frog populations and the area of land blocks in the buffer. Farmland management during the non-irrigation season was found to be diverse. The frog population was found to be affected by farmland management during the non-irrigation season. Species more dependent on paddy fi elds were more susceptible, with Pelophylax porosus brevipodus being the most affected. It was suggested that the tillage from December to April had a negative effect on the population of P. porosus brevipodus.