To measure land subsidence using satellite SAR data, PSInSAR analysis is effective because it can measure displacement with high accuracy, although it is limited to persistent scattering points only. Although PSInSAR analysis requires a large number of data observed under the same conditions to ensure measurement accuracy, it is possible to use Sentinel-1 SAR data, which does not have high spatial resolution but has a relatively high measurement frequency. In this paper, in the eastern Chiba Prefecture area, where the maximum land subsidence is about 2 cm/year, land subsidence was measured by PSInSAR analysis using Sentinel-1 SAR data of descending orbit for seven years from January 2017 to January 2024, and compared with the results of level surveys conducted once a year. The accuracy of displacement measurement by PSInSAR analysis using Sentinel-1 SAR data was about 5 mm, and the accuracy of displacement velocity measurement was about 1 mm/year, even when reference values were set for each relatively wide area.