A conference control device including a data transmission portion that transmits conferencing data from one of the conference terminal devices to another of the conference terminal devices, a first notification request portion that, in a case where a first request packet that requests establishing of a first communication path has been received from the one of the conference terminal devices while the conferencing data are transmitted by the data transmission portion, transmits a first notification request packet to the other of the conference terminal devices, and a first request response portion that, in a case where a first response packet providing notification of a port number for establishing the first communication path has been received from the other of the conference terminal devices, transmits to the one of the conference terminal devices a first request response packet containing information on a transmission source port number of the first response packet.