A mobile telephone communication system capable of curtailing request for hand off to a mobile telephone exchange is disclosed. The mobile telephone communication system of the present invention is constituted by a plurality of radio base station groups, and one mobile telephone exchange. The radio base station group is constituted by a plurality of subordinate radio base stations providing a speech service to a mobile telephone device, and one main radio base station controlling the plurality of subordinate radio base stations. In the case where the mobile telephone device moves within the radio base station group, the main radio base station switches the mobile telephone device between the plurality of subordinate radio base stations. In the case where the mobile telephone device moves from one radio base station group to a different radio base station group, a hand off indicating signal is transmitted from the mobile telephone exchange to the main radio base station so that the hand off is carried out between the radio base station groups.