To provide a radio communication apparatus and a mobile station sensitive to change in the radio environment. A mobile station corresponding to the HSDPA and transmitting the CQI information used for the adaptive modulation control executed by a radio base station, comprising a radio environment supervising unit for supervising change in the radio environment on the basis of the received signal from the radio base station, a CQI generating unit for generating the CQI information reflecting change in the reception quality from the radio base station in accordance with the result of supervising by the supervising unit, and a transmitting unit for transmitting the generated CQI information to the radio base station.