When there is a shooting location of another panoramic image in a shooting direction of a panoramic image to be displayed, a marker setting unit associates a marker, indicating the presence of the another panoramic image in the shooting direction, with the panoramic image to be displayed. A mapping processing unit maps the panoramic image to be displayed, which has been associated with markers for the other panoramic images, into a three-dimensional (3D) panoramic space as textures. A 3D image generator generates a 3D panoramic image when the 3D panoramic space is viewed in a specified line of sight, with the shooting location of the panoramic image to be displayed being set as a viewpoint position. An interface receives an instruction from a user concerning the displayed 3D panoramic image.