Provided are a reflective unit using an electroactive polymer and a flexible display. The reflective unit includes: an electroactive polymer layer which becomes strained when a voltage is applied thereto by an electrode; a light reflecting unit reflecting external light and having reflecting cells arranged on the electroactive polymer layer to be spaced apart from one another wherein a distance between the reflecting cells is changed according to the strain of the electroactive polymer layer; and a light blocking layer preventing external light from being reflected by the light reflecting unit and having blocking cells arranged over the light reflecting unit to be spaced apart from one another.