An image display device having a display panel, the device being utilized to form an image display system in which a plurality of the image display devices are arrayed in one or both of vertical and horizontal directions to display one image as a whole while an image allocated to each device is displayed via the corresponding display panel, the image display device includes a reading processing unit that reads out image information and delays start of output of this image information by a predetermined period of time determined based on the number of the image display devices which forms the image display system and a row to which the present device belongs in the vertical arrangement.