Disclosed is a novel scanning-probe type atomic force microscope wherein false deflection of probe is reduced. Probe of the scanning-probe type atomic force microscope moves in both the horizontal direction and the vertical direction during the scanning, while the sample is kept stationary. In order to reduce the false deflection brought to the probe due to the scanning motion, two approaches are adopted. The first is to have the focused laser spot tracking an invariant point on the probe's cantilever, which moves 3-dimensionally during the scanning. The second approach is to have the laser beam, which is reflected from the moving cantilever, hitting an invariant point of the PSD, when the sample is distanced from the probe and induces no deflection. A beam racking system wherein the scanning probe locates approximately at focus of objective lens and the optical system including a laser source, an optical module, a feedback module and the probe are driven by an approach mechanism to move in synchronization.