Network conferencing system, attendance authentication method and presentation method

A conferencing system made up of an attendant terminal, a presenter terminal and a chairman terminal is provided. Particularly, attendance authentication is carried out and the contents of a supplementary explanation given by a presenter are presented only to the presenter at the time of preview display. Attendant equipments attending a conference have a presentation function, a chat function, a file transfer function, a teleconference control function, a proceedings control function and a user authentication/equipment management function. On of a plurality of attendant electronic equipments acquires one of the authority to be the presenter terminal having the presentation function, the authority to be the chairman terminal having the authentication function, equipment management function and proceedings control function, and the authority to be the attendant terminal having the presentation contents browsing function. In such a network conferencing system, the authority of the chairman terminal having the authentication function, equipment management function and proceedings control function is given as well as the authority to be the attendant terminal and the presenter terminal, thus having a conference.