It is an object of the invention to provide a display unit consisting of a plurality of display devices which are substantially equivalently disposed at an appropriate interval optically or as seen from the side of the observer, even when the plurality of display devices are not disposed at the appropriate interval due to some technical restrictions.A display unit is provided with a plurality of display devices disposed one after the other on the line of sight of the observer; and an optical distance setting device, which is disposed between two adjacent display devices among the plurality of display devices, for setting the optical distance between the two display devices to a predetermined value that is different from the optical distance when the air is filled between the two display devices.