Provided are a communication system capable of causing a communication application to speedily find out whether D2D communication is possible or not. The phonebook server 300 includes a phonebook data acquisition unit 310 configured to acquire first phonebook data containing an identifier of a terminal 400B, a terminal location acquisition unit 320 configured to acquire a location of the terminal 400B contained in the first phonebook data acquired by the phonebook data acquisition unit 310, a phonebook data generation unit 330 configured to generate second phonebook data containing an identifier of a candidate terminal capable of direct communication, based on the location of the terminal 400B acquired by the terminal location acquisition unit 320, and a transmission unit 340 configured to send a terminal 400A the second phonebook data generated by the phonebook data generation unit 330.