To easily achieve higher security and to reject all data transmitted from a person except a conference attendee to a conference to constantly achieve a smooth progress of the conference in an ad hoc network consisting of a terminal with a radio function.

A group member list in which names and fraction address information of all members (including a host 10) participating in the conference are described is held by all terminals in the conference. Address information in data transmission is all obtained by each member terminal 11 by utilizing the list. In a radio electronic conference utilizing a radio communication system, the data of the terminal leaving the conference halfway are not allowed to be received as the data of the conference being presently held and after the terminal leaves the conference, contents of the conference is made impossible to be received.