THE BACK HORN is a rock band, formed in Tokyo, Japan in 1998.

The band started around April in 1998, when the original members all came to Tokyo from the countryside where they all lived, all for different reasons. They met, and decided to start a band. First called Gyorai, they soon changed their name to THE BACK HORN.

Following their first notable performance at the Fuji Rock Festival in 1999, they released a mini-album Doko e Yuku on Kando Records. Seven months after that, they released their first full-length, Yomigaeru Hi. After this, the band got signed to a major label, Speedstar Records. Although they, to this day, still remain on Speedstar Records' roster, they're still often thought of as an indie band. It was also around this time when Hirabayashi decided to leave the band.

It was only after the release of their first album release on Speedstar Records, Ningen Program, that they found a new bassist, Okamine Kohshu, though he wasn't immediately made a full-time member. He was however involved in recording of the next album, Shinzoo Orchestra, and while touring for the album, the band announced that he was now an official member.

As the band was becoming increasingly popular, they were asked to provide music for 2 movies: Kiyoshi Kurosawa's Akarui Mirai and Utada Hikaru's husband's Casshern, releasing the album Ikiru Sainou in between them.

After a couple of tours, including a show at the Rock In Japan festival, a couple of single releases and the release of their first live DVD, they released their 5th full-length, Headphone Children, considered by many to be a concept album. The song Kiseki from the album was used in the horror movie Zoo. The tour following Headphone Children was a huge success and the band decided to release a live album of it, entitled Ubugoe Chainsaw which contained the best performances of songs from the tour. 2 months later, BACK HORN played their first show in Europe, at a festival in Barcelona, Spain.

The band then released a couple of singles and did some shows again, including an acoustic street tour with only Yamada and Suganami, where they just performed on the streets of Japan for free. In April they released their 6th full-length, Taiyou no Naka no Seikatsu, and are currently on tour promoting it.