Aika Mitsui (光井 愛佳, Mitsui Aika, born January 12, 1993, Ōtsu, Shiga, Japan) is a member of Hello! Project and a former member of the J-pop group Morning Musume, joining as a member of the eighth generation from the audition in Japan during December 2006. Mitsui's audition process was documented during the late 2006 episodes of Hello! Morning. She performed Ayumi Hamasaki's "Blue Bird" in round one of her audition and Morning Musume's "Furusato" and "Osaka Koi no Uta" in rounds two and three.