A mobile station apparatus (100, 300, 500) that performs multicarrier communication with a base station apparatus, the mobile station apparatus comprising: a communication quality measuring section that measures communication quality of each of chunks, into which a plurality of subcarriers in a frequency domain is divided, based on a known signal; a transmitting section that transmits feedback information based on the communication quality of each of the chunks to the base station apparatus; a relative value calculating section (150, 320, 520) that calculates a relative value of communication quality from the communication quality of each of the chunks; a feedback information generating section (155, 330, 530) that generates the feedback information from an absolute value of communication quality of a reference chunk and the relative value; and a report granularity determining section that determines a report granularity for reporting the relative values of communication quality based on the measured communication quality, wherein: the relative value calculating section (150, 320, 520) calculates converted relative values by converting the relative values of the communication quality according to the report granularity for reporting; and the feedback information generating section (155, 330, 530) generates the feedback information from the absolute value of communication quality of the reference chunk, the converted relative values and the report granularity for reporting. a communication quality measuring section that measures communication quality of each of chunks, into which a plurality of subcarriers in a frequency domain is divided, based on a known signal; a transmitting section that transmits feedback information based on the communication quality of each of the chunks to the base station apparatus; a relative value calculating section (150, 320, 520) that calculates a relative value of communication quality from the communication quality of each of the chunks; a feedback information generating section (155, 330, 530) that generates the feedback information from an absolute value of communication quality of a reference chunk and the relative value; and a report granularity determining section that determines a report granularity for reporting the relative values of communication quality based on the measured communication quality, wherein: the relative value calculating section (150, 320, 520) calculates converted relative values by converting the relative values of the communication quality according to the report granularity for reporting; and the feedback information generating section (155, 330, 530) generates the feedback information from the absolute value of communication quality of the reference chunk, the converted relative values and the report granularity for reporting. the relative value calculating section (150, 320, 520) calculates converted relative values by converting the relative values of the communication quality according to the report granularity for reporting; and the feedback information generating section (155, 330, 530) generates the feedback information from the absolute value of communication quality of the reference chunk, the converted relative values and the report granularity for reporting.