Abstract: To hide a difference in call reference mode at a protocol control section from a basic call control section which provides an added service based on a plural call reference mode, a distributing section 21 of a virtual terminal control device 20 determines whether an event (signal) of a call reference correspondence from a basic call control section 10 is connectable or not to a terminal 40 via a protocol control section 30, and delivers the signal to an actual terminal processing section 22 or a virtual terminal processing section 23. In response to receipt of signals from the basic call control section, the protocol control section and the virtual terminal processing section, the actual terminal processing section determines and executes an operation per state while shifting the state, and transfers the signal to the protocol control section and the basic call control section while converting a call reference of the signal.