Abstract: A three-dimensional display apparatus includes a case, illuminators, a first mirror, a diffractive optical element and a second mirror. The case can contain an object for display, and includes a movable leaf operable to open and close the case. The illuminators are located around the case for emitting light onto the object. The first mirror is disposed in the case for carrying the weight of the displayed object and reflecting light reflected by the object. The diffractive optical element is located on the case and formed with cells each including portions of regularly changing thicknesses for diffracting the light reflected by the first mirror. The second mirror is located on the diffractive optical element for reflecting the light diffracted by the diffractive optical element, thus forming an image of the displayed object between itself and the diffractive optical element.