According to one embodiment, a stereoscopic image display device includes a three-dimensional pixel unit, a backlight, and an arithmetic/control circuit. The three-dimensional pixel unit includes a plurality of pixel cells that are formed of an optical material having electrically changeable optical characteristics, are arranged in a mutually separated manner and in a three-dimensional manner, and are electrically connected with transparent wiring patterns. The backlight is configured to emit illumination light to the three-dimensional pixel unit. The arithmetic/control circuit is configured to control the plurality of pixel cells individually via the wiring patterns on the basis of input three-dimensional image data to cause the three-dimensional pixel unit to function as a transmissive hologram.