Koshi Inaba (稲葉浩志) is a Japanese singer-songwriter and music producer, best known as the vocalist and lyricist of the Japanese rock duo B'z.

Inaba began his music career as a backing musician at Being. After Daiko Nagato, the founder and music producer of Being, listened to his demo, they chose Inaba to be the vocalist for B'z. He made his debut with the band on 21 September 1988, alongside producer Tak Matsumoto (松本孝弘).

In B'z, Inaba began contributing to the production side starting with their song “ねがい (Negai)”. Following that, he released his first solo album マグマ (Magma), in 1997, which reached first place on the Oricon Chart and achieved sales of over one million copies.

In addition to his work with B'z, Inaba is also the vocalist for the group INABA / SALAS with American music producer Stevie Salas.

As of 2024, Inaba has released five solo studio albums, including his latest, 只者 (Tadamono), which was released on 26 June 2024.