Abstract: A hologram apparatus comprises a rotary plane with a plurality of holograms concentrically or spirally arranged thereon, a light emitting source, and at least one photodetector for reading out reconstructed images of the holograms. During rotation of the rotary plane, the optical path of a light beam from the light emitting source is controlled, whereby the reconstructed images from the respective holograms are focused on the photodetector in succession. Some or all of the holograms are substantially oblong, and the long side and the short side of each oblong extend radially about the axis of the rotary plane and substantially orthogonally to the radial direction respectively.