A stereoscopic image display device includes a display panel provided with a pixel array, a rendering processing unit that performs rendering for odd left image data and even right image data during an n-th frame period, and performs rendering for odd right image data and even left image data during a (n+1)-th frame period, a patterned retarder including a first retarder that transmits light so as to be modulated into first circularly polarized light and a second retarder that transmits light so as to be modulated into second circularly polarized light, active retarder glasses including a first active retarder that transmits one of the first circularly polarized light and the second circularly polarized light, and a second active retarder that transmits the remaining one of the first circularly polarized light and the second circularly polarized light, and a control unit that generates a switchable control signal.