A scanning probe microscope includes (a) a first device which causes a relative displacement between an object and a probe, (b) a detector which detects a change in interaction caused by the first device between the probe and the object, (c) a second device which feeds the detected change back to the relative displacement to keep the interaction equal to a constant, (d) an adder which adds the detected change to the constant while the interaction is fed back to a distance between the probe and the object, to thereby temporarily vary the constant, (e) a collector which collects signals relating to a displacement which signals are varied as the constant is varied, and calculates a relation among the signals, and (f) a third device which returns the temporarily varied constant back to the constant for scanning the object, calculates products of the relation with each of the signals in real-time, and sums the products, which products indicate a profile of a surface of the object.