A communication device includes: a first transmitting unit that transmits pattern information specifying a pattern of an offer and an answer in Session Initiation Protocol (SIP) to a called side machine corresponding to a pattern transmitting the offer from the called side machine; a presenting unit that presents called side machine information when the offer transmitted from the called side machine according to the pattern specified in the pattern information and the called side machine information to identify the called side machine are received; and a second transmitting unit that establishes a session with the called side machine by transmitting the answer to the called side machine when a predefined condition is satisfied after the presenting unit presents the called side machine information.