Provided is an image display device capable of adjusting brightness. The image display device includes a brightness determining unit that determines the brightness of image data, applied from outside, so as to output a backlight selection signal and a contrast selection signal; a backlight control unit that is connected to the brightness determining unit and outputs a backlight driving voltage for supplying backlight with brightness corresponding to the backlight selection signal; a contrast control unit that is connected to the brightness determining unit and outputs an image output signal for outputting an image of which the contrast is adjusted to correspond to the contrast selection signal; and an image display unit that is connected to the backlight control unit and the contrast control unit and receives the backlight driving voltage and the image output signal so as to display an image in which the brightness of the backlight and the contrast of the image data are respectively adjusted.