A radio communications system having a radio base station and a radio relay station is disclosed. A terminal performs radio communications through a link with the radio base station or a link with the radio base station via the radio relay station. The radio base station includes an antenna gain pattern switching part configured to switch between an omnidirectional antenna gain pattern and an adaptive array antenna gain pattern forming a beam; and a control part configured to direct the beam to the terminal in one of an extended service area covered by the adaptive array antenna gain pattern outside a regular service area covered by the omnidirectional antenna gain pattern and the service area of the radio relay station by causing the antenna gain pattern switching part to switch to the adaptive array antenna gain pattern.