|Full Name: Mika Koizumi|
|Ranger Designation: Yellow Four|
|Weapon : Thunder Sword|
|Mecha : Bio Jet 2|
|Vehicle : Bio Machine 2|
Abilities: Action Shooting, Strobe Flash, and Chodenshi (Super Electron) Holograph
Mika was originally a photographer who was hesitant at first to join Bioman. She was the more hard driven female of the two. In fact, she was the first female yellow ranger.
Suit actor: Hirotsugu Tsuuji (also plays Ju-Oh in Bioman)