A micro-iris unit may include: a support member disposed on a transparent substrate to form a fluid accommodating space in a central portion of the transparent substrate; a first fluid provided in the fluid accommodating space; and a second fluid provided in the fluid accommodating space and being movable by an electrical field or electromagnetic force. A side surface of the support member may include flexures or concave-convex portions to allow an area of contact with the first fluid or the second fluid to be significantly increased.