A stereoscopic image display device includes: a display unit including a plurality of pixels arranged in a matrix format, the pixels including left-eye and right-eye pixels alternately arranged in one direction; a memory including a left-eye image area for storing left-eye image data corresponding to the left-eye pixels and a right-eye image area for storing right-eye image data corresponding to the right-eye pixels; an address comparator for the respectively storing the left-eye and right-eye image data at corresponding addresses of the left-eye and right-eye image areas and making an arrangement of the left-eye and right-eye image areas in the memory in response to a first signal; a data synthesizer for synthesizing a stereoscopic image signal from the data stored in the memory; and a data driver for applying a data signal corresponding to a stereoscopic image signal to the display unit.