To provide a public telephone set system, satisfactorily maintaining the sanitary state of the transmitter/receiver of a public telephone set at the time of using the public telephone set.

This public telephone set system is provided with plural transmitters/ receivers, which can be physically and electrically connected to and separated from a telephone set main body, the telephone set main body in a system enabling speech by being connected to and separated from one of the transmitter/receiver, and a charging system for executing charging according to the connection and separation. When a transmitter/receiver side connector 11 of the transmitter/receiver 1 constituted of a microphone 13, a speaker 14, and a memory 12 is physically and electrically connected with a main body side connector 21 of the public telephone set main body 2, the classification and charging system of the transmitter/receiver 1 is identified, and an off-hook state is obtained, and when a telephone number or the like is inputted by a push type dial 26, mutual speech can be realized, and the charging system can be started. After the end of the mutual speech, by having the transmitter/receiver side connector 11 separated so, the execution of the charging system can be ended, and simultaneously an on-hook state can be obtained.