1. An information processing apparatus in a three-dimensional virtual reality space sharing system in which a plurality of information processing units for displaying a three-dimensional virtual reality space image by acquiring three-dimensional graphic data associated with a basic object to be commonly used by a plurality of users and an update object to be updated according to an operation performed by each of said plurality of users are interconnected with a shared server terminal for transferring update data associated with updating of a state of said update object transmitted from each of said plurality of information processing units to another of thereof, said information processing apparatus comprising: a positional information acquisition processing means for acquiring updated positional information associated with a position of said update object relative to said three-dimensional virtual reality space based on the update data transferred from said shared server terminal; evaluating means for evaluating the updated positional information and determining therefrom whether the position of the update object is within a particular portion of the three-dimensional virtual reality space; and a superimposed display processing means for displaying the updated positional information acquired by said positional information acquisition processing means onto said three-dimensional virtual reality space image in a superimposed manner but only if the evaluating means determines that the position of the update object is within the particular portion of the three-dimensional virtual reality space.