A synthetic aperture processing system (10, 20, 30) comprising: transmission means for generating a frequency-modulated wave having a time-varying frequency and radiating the frequency-modulated wave to an irradiation region from a plurality of measuring sites; reception means for receiving a plurality of reflected waves caused by the plurality of frequency-modulated waves radiated from the transmission means; range compression means for range-compressing each of the reflected waves received by the reception means and generating reception data consisting of a plurality of sinc functions; correlation value calculation means (18, 28) for, based on a plurality of model data segments consisting of a plurality of sinc functions obtained by range compression of ideal reception waves caused by the reflection of the frequency-modulated waves at a plurality of predetermined sites in the irradiation region and the reception data generated by the range compression means, calculating correlation values representing a degree of correlation between each of the model data segments and the reception data; model data calculation means for calculating the model data segments used by the correlation value calculation means, for each of the determined sites in the irradiation region in accordance with the frequency-modulated wave generated by the transmission means wherein the model data calculation means extracts data sets at two points having a predetermined distance on both sides of the peak from each sinc function constituting the model data segment to calculate the model data segment using the extracted data sets; and the correlation value calculation means (18, 28) further comprises: selection means for selecting data sets at two points as sample data from each of the sinc functions constituting the reception data for each of the model data segments calculated by the model data calculation means in accordance with the position information of the data sets at two points for each sinc function constituting the model data segments, and cross-correlation computation means (18, 28) for performing the cross-correlation computation between sample data of the reception data selected by the selection means and the data sets of the plurality of model data segments to calculate the correlation values; and output means for outputting the correlation values calculated by the correlation value calculation means. transmission means for generating a frequency-modulated wave having a time-varying frequency and radiating the frequency-modulated wave to an irradiation region from a plurality of measuring sites; reception means for receiving a plurality of reflected waves caused by the plurality of frequency-modulated waves radiated from the transmission means; range compression means for range-compressing each of the reflected waves received by the reception means and generating reception data consisting of a plurality of sinc functions; correlation value calculation means (18, 28) for, based on a plurality of model data segments consisting of a plurality of sinc functions obtained by range compression of ideal reception waves caused by the reflection of the frequency-modulated waves at a plurality of predetermined sites in the irradiation region and the reception data generated by the range compression means, calculating correlation values representing a degree of correlation between each of the model data segments and the reception data; model data calculation means for calculating the model data segments used by the correlation value calculation means, for each of the determined sites in the irradiation region in accordance with the frequency-modulated wave generated by the transmission means wherein the model data calculation means extracts data sets at two points having a predetermined distance on both sides of the peak from each sinc function constituting the model data segment to calculate the model data segment using the extracted data sets; and the correlation value calculation means (18, 28) further comprises: selection means for selecting data sets at two points as sample data from each of the sinc functions constituting the reception data for each of the model data segments calculated by the model data calculation means in accordance with the position information of the data sets at two points for each sinc function constituting the model data segments, and cross-correlation computation means (18, 28) for performing the cross-correlation computation between sample data of the reception data selected by the selection means and the data sets of the plurality of model data segments to calculate the correlation values; and selection means for selecting data sets at two points as sample data from each of the sinc functions constituting the reception data for each of the model data segments calculated by the model data calculation means in accordance with the position information of the data sets at two points for each sinc function constituting the model data segments, and cross-correlation computation means (18, 28) for performing the cross-correlation computation between sample data of the reception data selected by the selection means and the data sets of the plurality of model data segments to calculate the correlation values; and output means for outputting the correlation values calculated by the correlation value calculation means.