Shimōsa-Toyosato Station was opened on March 11, 1933 as a station on the Japanese Government Railway (JGR) for both freight and passenger operations. After World War II, the JGR became the Japan National Railways (JNR). Scheduled freight operations were suspended from October 1, 1971. The station has been unattended since March 1, 1985. The station was absorbed into the JR East network upon the privatization of the Japan National Railways (JNR) on April 1, 1987. The station building was rebuilt in 2008.