An IP (Internet Protocol) telephone terminal includes a communication subsection transmitting and receiving data to and from one or more IP telephone terminals on a peer-to-peer connection over an IP network, and a search subsection comparing a telephone number received by the communication subsection with a telephone number allotted to the IP telephone terminal. When the result from comparison indicates a coincidence between both of the telephone numbers under comparison, the communication subsection transmits the IP address assigned thereto. The IP address thus transmitted efficiently allows a call connection to be set up from a calling telephone terminal having transmitted the telephone number.