The present invention provides a mobile communication system that can efficiently control the conflicting abilities of making the high quality communication and keeping the number of accommodating the mobile terminals.A radio quality measuring part of a mobile terminal requests a radio base station to increase or decrease the transmitting power to attain a needed receiving quality. A radio quality control part controls the receiving quality so that the bearer quality may attain the required quality on the basis of the bearer quality measured by a bearer quality control part. The radio base station always monitors the quality for a radio section. When this radio quality exceeds a threshold specified by a radio base station controller, the radio base station reports to the radio base station controller the worsening or improvement of the radio quality via a radio base station protocol terminator with a radio quality report.