Ichihosawa Dam (Japanese: 一の沢ダム) is an earthfill dam located in Hokkaido Prefecture in Japan. The dam is used for irrigation. The catchment area of the dam is 0.6 km. The dam impounds about 2 ha of land when full and can store 168 thousand cubic meters of water. The construction of the dam was started on 1924 and completed in 1927.