To suppress the number of terminals possible to directly attain two-way communication of video or sound or the like with a server on the basis of user's utterance request detection and reduce transmission delay, communication failure, and server's load.

A server is connected with a plurality of information terminals via network and the information terminals are grouped into one or plural terminal groups according to the predetermined set condition. One terminal group includes one representative terminal possible to directly receive shared information from the server and a participating terminal for receiving distribution of shared information from the representative terminal. The information terminal is provided with an utterance detection section for detecting an utterance request of users and an utterance request section for transmitting utterance request information to a server. The server is provided with a two-way communication control section that switches a communication state between the information terminal and the server to a two-way communication state possible to directly and mutually transmit and receive the shared information when the server receives the utterance request information.