A communication terminal device includes a terminal body which enables a communication with a radio communication network by a first radio communication, a separating member which may be separated from the terminal body and enables a communication with the terminal body by a second radio communication, a tripartite communication unit which enables a tripartite communication among the terminal body, the separating member, and the radio communication network when the separating member and the terminal body are separated, and a control unit which controls howling between the terminal body and the separating member when the separating member and the terminal body are close during the tripartite communication.