Images and voice data of conference call participants are transmitted to user terminals to permit video conference calling. Mobile terminals receive moving images of only the current speaker to permit easy recognition of the visual image on the relatively small display terminal of the mobile user. A multipoint controller distributes two types of distribution streaming data, first and second distribution streaming data. The first distribution streaming data are constituted of moving images transmitted from all of user terminals. The second distribution streaming data contain only the moving image from the user terminal of the current speaker, among the user terminals. The first distribution streaming data are used as distribution information for user terminals such as a personal computer or a video conference-dedicated terminal, while the second distribution streaming data are used as distribution information for mobile user terminals such as a mobile telephone and a PDA.