Terminal management information concerning a plurality of communication terminals of a user is managed. When a call addressed to the user is initiated, one or more terminals that can accept the call is identified by referring to an ability needed for a communication involved in the call and the terminal management information concerning the plurality of communication terminals managed by the step (a). Information involved in the call into items of information to be sent to the above one or more terminals identified by the step (b) and combining items of information from the above one or more terminals identified by the step (b) is separated into information to be sent to one of the plurality of communication terminals that initiates the call. A virtual terminal is formed by the above one or more terminals identified by the step (b) and communicates with the above one of the plurality of communication terminals.