The author compared the Persistent Scatterer Interferometry (PSI) results of different radar wavelengths; L- and C-band. The density of identified Persistent Scatterer (PS) points depends on the spatial resolution of the data in urban areas. In addition, L-band is capable of finding out PS points in vegetated area, while C-band is not. Measurement errors of individual PS points are 8-11 mm for L-band and 2-3 mm for C-band, almost proportional to the wavelengths. This suggests that the shorter wavelength is more suitable for pointwise usage such as infrastructure monitoring. Measurement errors of spatially averaged 30 PS points are 4-6 mm and about 2 mm/yr, being independent of wavelength, according to the comparison with continuous GNSS observation results. This means that L-band has a comparable capability of detecting spatially distributed deformation to C-band.