It is possible to provide a radio communication system, a radio base station device, and a radio terminal device capable of reducing the power consumption in a radio terminal device without thinning pilot signals used for measuring upstream line quality. In the radio base station device (100) used in a radio communication system using different frequency bands for the upstream line and the downstream line, an upstream line pilot generation unit (115) forms a CQI measuring pilot signal and an upstream line RF unit (105) transmits the communication quality measuring pilot signal by using the upstream line use frequency band in the upstream line pilot transmission section. Thus, the upstream communication quality measuring pilot signal used by the radio base station device (100) to measure the line quality is transmitted by using the upstream line frequency band and accordingly, it is possible to reduce the power consumption in the radio terminal device.