Ichiro Mizuki (水木 一郎, Mizuki Ichirō ), born Toshio Hayakawa (早川 俊夫, Hayakawa Toshi ) (born January 7, 1948), is a famous, highly prolific Japanese vocalist best known for his work on theme songs for Tokusatsu and Anime, having performed numerous theme songs for Japanese film, television, video and video games. He is referred to by fans and fellow performers alike as the aniki (アニキ, aniki? "big brother") of the anison, or anime music genre. As such, he is popular known as "Aniki", an informal way of referring to an older brother. In terms of fame, he is only rivalled by a handful of anison singers, most of whom joined him in forming the group JAM Project.

Mizuki is perhaps most famous for his earlier performances: the opening theme songs of the Go Nagai animated television series Mazinger Z, Leiji Matsumoto's Space Pirate Captain Harlock and Tatsunoko Productions' Tekkaman: The Space Knight — Mazinger Z will later give birth to the Super Robot genre of anime that dominated the Japanese television landscape of the 1970s.

On July 19, 2000, he formed (with fellow anison vocalists Hironobu Kageyama, Masaaki Endoh, Eizo Sakamoto, and Rika Matsumoto) the "supergroup" JAM Project. (Effective August 2002, he has since reduced his formal status in this group to "part-time member" and now focuses on producing both the group and up-and-coming talent.)

His most recent performance was STORMBRINGER, the opening of Kotetsushin Jeeg (as part of JAM Project). Fittingly enough, Kotetsushin Jeeg is a sequel to Kotetsu Jeeg, an anime which Mizuki sang the opening theme for.