A displacement detection mechanism for a vibrationally driven cantilever includes a vibration frequency detector comprised of an LC resonator that detects a change of capacitance between the cantilever and a sample surface due to a change of vibration of the cantilever, and an F-V converter or an FM demodulator that detects a voltage based on the vibration frequency, whereby displacement of the cantilever can be detected. The displacement detection mechanism can be used in a scanning probe microscope to perform shape measurement and physical property measurement without the presence of light.