"AED" is a kind of haptic display for virtual reality. The conventional haptic display generates force to display haptic sensation. However, this system displays haptic sensation by imitating the shape of the object. The user could get haptic sensation by touching the imitated surface of the object. The AED has the unit that consists of the element of arbitral shape of surface. Then by controlling the unit appropriately, the system could imitate the arbitral shape of the surface. This is the principle idea of AED, Active Environment Display.