Patent ID: 8490209

Claim:
A surface state measuring device for measuring surface state of a sample by detecting modulation of the oscillations of the probe arranged over the sample, comprising: an excitation mechanism for exciting a cantilever having a probe; scanning mechanism for making the probe scan the sample by moving the probe and the sample relative to each other; an alternating force generator for generating an alternating force between the sample and the probe, by a signal having a single frequency not being resonance frequencies of the cantilever; a modulation measuring mechanism for measuring degree of periodic frequency modulation of the oscillation of the probe, which is caused by a periodic change of effective spring constant of the cantilever having the probe caused by attracting force and repulsive force which are periodically applied to the probe by the alternating force, by employing frequency demodulation, by amplitude demodulation, or by an intensity of a sideband spectrum among sideband spectrums generated by the frequency modulation.