To provide an image display device capable of changing the image formation distance of a display image so that an observer can observe the image in the most suitable state.

When a display image is inputted to an image input part 11, the input part 11 outputs the inputted image to a hologram calculation part 13. When an observer specifies an image formation distance between the observer and an image formation face for the display of the display image to an image formation distance specification part 12, the specification part 12 outputs the specified image formation distance to the calculation part 13. The calculation part 13 supposes that the display image inputted from the input part 11 is located on the image formation face of the image formation distance specified by the specification part 12 and calculates the hologram pattern of light propagated from the image formation face and reference light radiated from a reference light source on a hologram face. A hologram reproducing part 14 displays the hologram pattern calculated by the calculation part 13 on a spatial light modulating device and reproduces the hologram by the irradiation with reference light.