A radio communication apparatus that performs radio communication according to a multicarrier scheme, the radio communication apparatus comprising: a transmitting unit that includes a null inserting unit that dispersedly arranges null symbols in a two-dimensional space of time and frequency in radio data, and a differential modulating unit that performs differential modulation on a data symbol part other than the null symbols; and a receiving unit that includes an interference measuring unit that measures interference power for a data symbol that is a measurement target by using a null symbol adjacent to the data symbol in the two-dimensional space of time and frequency, and a delay detecting unit that performs weighting on each data symbol according to the interference power measured for each data symbol and that performs delay detection between data symbols; wherein the differential modulating unit performs differential modulation by switching an interval between symbols from which a differential is obtained according to number of null symbols between two data symbols on which differential modulation is performed and combining differential modulations in which intervals between differential symbols are different, and the delay detecting unit performs delay detection by switching an interval between symbols for delay detection according to number of null symbols between two data symbols on which delay detection is performed and combining delay detections in which intervals between symbols are different. a transmitting unit that includes a null inserting unit that dispersedly arranges null symbols in a two-dimensional space of time and frequency in radio data, and a differential modulating unit that performs differential modulation on a data symbol part other than the null symbols; and a null inserting unit that dispersedly arranges null symbols in a two-dimensional space of time and frequency in radio data, and a differential modulating unit that performs differential modulation on a data symbol part other than the null symbols; and a receiving unit that includes an interference measuring unit that measures interference power for a data symbol that is a measurement target by using a null symbol adjacent to the data symbol in the two-dimensional space of time and frequency, and a delay detecting unit that performs weighting on each data symbol according to the interference power measured for each data symbol and that performs delay detection between data symbols; wherein an interference measuring unit that measures interference power for a data symbol that is a measurement target by using a null symbol adjacent to the data symbol in the two-dimensional space of time and frequency, and a delay detecting unit that performs weighting on each data symbol according to the interference power measured for each data symbol and that performs delay detection between data symbols; the differential modulating unit performs differential modulation by switching an interval between symbols from which a differential is obtained according to number of null symbols between two data symbols on which differential modulation is performed and combining differential modulations in which intervals between differential symbols are different, and the delay detecting unit performs delay detection by switching an interval between symbols for delay detection according to number of null symbols between two data symbols on which delay detection is performed and combining delay detections in which intervals between symbols are different.