PURPOSE: To prevent division and disappearance of a charging signal to ensure transmission and receiving of the charging signal, by transmitting the charging signal from a control station after confirming the signal transmitted from a mobile station during connection.

CONSTITUTION: Plural mobile stations TS and base stations ZN1∼ZNn are controlled by a control station MS to constitute radio service lines between a public telephone set TELP of the mobile station TS and subscriber's telephone set TEL1∼TELn connected to an exchange EX2 of a telephone station PS in the public corporation side. This control station MS is provided with an exchange EX1 which switches base stations ZN1∼ZNn selectively, a trunk TRK which connects the exchange EX1 and a telephone line LP to the telephone station PS, and a signal transmitter and receiver KSR. A charging signal Kd given from a charging control part KCT of the telephone station PS to the trunk TRK is stored temporarily, and a signal fsd from the mobile station TS is monitored by a timer circuit; and after confirming the existence of the signal fsd, AND between this signal and the charging signal Kd is operated to transmit a charging signal fa.