Monoi Station originated as the Monoi Signal (物井信号所?) on the Japanese Government Railway (JGR), established on March 4, 1911. It was upgraded to the Monoi Signal Stop (物井信号場?) on April 1, 1922 and to a full passenger station on April 5, 1937. After World War II, the JGR became the Japan National Railways (JNR). The station was absorbed into the JR East network upon the privatization of the Japan National Railways (JNR) on April 1, 1987. A new elevated station building was completed on April 12, 1998. The platforms were lengthened in 2004 to accommodate 15-carriage trains.