The band, originally called “Planet,” was formed by four friends for a one-time performance at a high school culture festival. But they decided to continue playing because of how well they were received at the festival and how much fun they were having. The band was afviced by Toshiba EMI to change their name after sending their demo tapes to record labels and they chose Base Ball Bear which they got from Chocolate's song, Base Ball and Elvis Presley. The band currently has Yūsuke Koide on Vocals and guitar, Shiori Sekine on bass guitar and backing vocals and Daisuke Horinouchi on drums and chorus. Shōhei Yuasa, who used to play the guitar along with them, left the band on March 2nd, 2016.