For reducing the load on a server as much as possible during transfer of data from the server to a terminal, each terminal is capable of playing out a network game in cooperation with a local network game terminal. To this end, the local network game terminal and one or more other network game terminals are grouped in the local network game terminal. Additionally, group information is generated with which the game server 1 can recognize the grouped terminals as one user group, and representative terminal information is also generated with which other network game terminals in the same user group can recognize that the local network game terminal is the representative terminal. Bi-directional communications, including transfer of the data received from the game server 1 and the representative terminal information, are made with other network game terminal(s) in the user group.