In a network game in which a number of players participate, multiple players can communicate each other by the user of an IP telephone or an Internet telephone network. A voice receiving section of the terminal unit 12 comprises a game communicating section 51 connected to a game server via the network, a participant IP managing section 53 for managing IP addresses of game participants connected online to the network, a network receiving section 54 for receiving telephone message data and musical sound data via the network, a sorting section 55 for determining whether received telephone message data includes a prespecified IP address or not and sending a result of determination to a following extending section 56, the extending section 56 for restoring the transmitted telephone message data and musical sound data, a synthesizing section 57 for synthesizing the restored telephone message data and musical sound data in the time-series mode, and a microphone/speaker I/F section 59 as a connecting section to a microphone/speaker or other analog equipment.