A dynamic mode AFM apparatus for allowing high-speed identification of atoms of a sample surface, which comprises a scanner for performing three-dimensional scanning; an AC signal of a resonance frequency in a mode with flexural vibration of a cantilever; an AC signal of a second frequency which is lower than the frequency of the flexural vibration; a probe-sample distance modulated with the second frequency; a detector for detecting fluctuation of the resonance frequency; a detector for detecting vibration of the cantilever; and a detector for detecting a fluctuation component which is contained in a detected signal by detecting the resonance frequency fluctuation and synchronized with a modulation signal of the probe-sample distance, wherein an inclination of the resonance frequency against the probe-sample distance is obtained from the strength and polarity of the fluctuation component.