1. An image display apparatus comprising: a storage configured to store an object image, associated with information on a shooting direction, a first virtual spherical image having a first three dimensional (3D) inner surface, associated with first directional information, and a second virtual spherical image having a second 3D inner surface, associated with second directional information, where the first virtual spherical image and the second virtual spherical image are in the form of spheres; a mask region extraction unit configured to extract a region that is to be masked in the object image; a mask processing unit configured to generate the object image where the region to be masked in the object image is masked; a positioning unit configured to adjust the first directional information of the first virtual spherical image to be the shooting direction of the object image; a mapping processing unit configured to: (i) position the first virtual spherical image centered within the second virtual spherical image about a central point such that the first directional information and the second directional information align, (ii) map the mask-processed object image onto the first 3D inner surface of the first spherical virtual image such that the shooting direction and the first directional information are aligned, (iii) map at least one first virtual object onto the first 3D inner surface of the first virtual spherical image when a distance from the central point to the at least one first virtual object is within the first virtual spherical image, and (iv) map at least one second virtual object onto the second 3D inner surface of the second virtual spherical image when a distance from the central point to the at least one second virtual object is outside the first virtual spherical image such that the at least one second virtual image appears in the mask area from the viewer's point of view in the shooting direction in a three-dimensional (3D) object space; a three-dimensional (3D) image generator configured to generate a three-dimensional (3D) object image, when the 3D object image mapped by the mapping processing unit is viewed in a specified line of sight in such a manner so as to regard a shooting location of the object image as a viewpoint position; and a display control unit configured to display the 3D object image on a screen.