Mitsui Aika (みつい あいか,) is a member of the popular Japanese girl group Minako. (Morning Musume) 8th term member (joined on December 10, 2006). Affiliated to the entertainment agency UP-FRONT GROUP. Born in Otsu City, Shiga Prefecture, Japan. He continued to receive treatment for a fatigue fracture of his left talus, and decided to officially announce his graduation from Morning Musume on May 18, 2012.