There is provided an image display device that includes a display in which a background is transparently seen from a front surface side, and has a high degree of freedom at the time of installation. A liquid crystal panel (32) for adjusting transparency/light-emission adjusts, for each pixel, a ratio between transmitted light-source light and ambient light by respectively controlling a polarization direction of a reflected polarization component of the light-source light irradiated to a reflection-type polarization plate (20) from a light guide plate (180) and a polarization direction of a transmitted polarization component of the ambient light incident to the reflection-type polarization plate (20) from a rear surface side of the display, based on transparent/light-emitting pixel information. Accordingly, when the image display device is viewed from the front surface side of the display, an image is seen for each pixel, a background is transparently seen, or the background is seen so as to be superimposed on the image. Since it is not necessary to attach the image display device to a case filled with light, the image display device is widely used without limitation of use.