The present invention relates to a sub band notification method and apparatus in which a terminal notifies a base station of an optimum sub band that is determined based on radio link quality of a plurality of sub bands. The terminal apparatus measures the radio link quality of a current sub band that is currently assigned to it, and the radio link quality of the sub bands on both sides of the current sub band, compares the radio link quality of each sub band, then generates sub-band-change-request data that specifies that the optimum sub band is the sub band having a higher frequency than the current sub band, or the sub band having a lower frequency, and transmits that sub-band-change-request data to the base station.