An image display device adjusts display luminance in accordance with a surrounding illuminance. Since the display luminance considered to be appropriate differs depending on a user, the image display device includes a display unit operating according to a display luminance calculated based on the surrounding illuminance. For example, in the image display device, a user can set a range of the display luminance as a predetermined rule. The image display device provides a user interface enabling a user to easily input the predetermined rule or perform the setting input without being aware of it. That is, when the surrounding illuminance is above a predetermined illuminance, an input bar indicates only the range where the maximum value can be set as an input screen and when the surrounding illuminance is below the predetermined illuminance, the input bar indicates only the range where the minimum value can be set.