The line started out with the section between Shin-Sakuradai and Kotake-Mukaihara, and began through operations with The Eidan Subway Yūrakuchō Line (Now Tokyo Metro). At this point, the line did not connect with any other Seibu Line, thus making it so that only Eidan trainsets were used. In 1994, the sector between Shin-Sakuradai and Nerima opened, connecting with the Seibu Ikebukuro Line. Because of track elevation work at Nerima, only one track was used. Later in 1998, the sector between Shin-Sakuradai and Nerima became 2 tracks, and also began through service with the Ikebukuro Line.
