An avatar acting in a shared virtual space is changed in a manner nearly resembling that in a real space. A client PC, along with another client PC, is connected to a shared server through the Internet to receive data about the shared virtual space constituted by a VRML file from the shared server and displays the received data on a CRT monitor. A virtual life object (called an avatar), the alter ego of a user, is changed based on a growth parameter that changes according to occurrence of an event. A hard disk holding a growth parameter control table stores growth parameters updated by an event caused by an operation performed on own client apparatus or another client apparatus or an event caused by passing of predetermined time. The update growth parameter is also transferred to another client PC through the shared server.