Out of viewers of the same content, multi-user talking service is provided to only viewers who wish to enjoy the content in a large number of people. Only when an address of a terminal 4, 5 that has transmitted a request for participation in multi-user talking is registered in a viewer management DB (which manages viewers of contents), a content distribution/multi-user talking service center 1 registers the above-mentioned address into a participant management DB (which manages participants in multi-user talking) associating the address with identification information of a content that is registered in association with the address in question in the viewer management DB. Then, for each content, respective pieces of talking data received from addresses registered in association with identification information of said content in the participant management DB are synthesized to generate multi-user talking data, and generated multi-user talking data is transmitted to each of said addresses.