Communication terminal apparatus and a communication control method and communication control program

A user who received an invitation to a session to facilitate the determination of whether to participate in the session to allow the understanding of the contents of the conversation that had been exchanged in the session prior to participation in the session. The invitation request transmitting section 202 that transmits an invitation request to invite another station user in a communication session, invite accept transmission unit that transmits an invitation acceptance response according to the input operation of the local station user when receiving an invitation request from another station 206, a digest request transmitting section 206 that transmits a digest request if a predetermined condition is satisfied with respect to the invitation request received from another station, the transmission to create a digest information when receiving the digest request from another station a digest information transmitting section 210, a digest information output section 213 for notifying the content of the digest information received from the other station to own station user provided.