A laser beam adjustment unit adjusts a laser beam applied to a cantilever. Assuming that a direction of displacement of a spot of the laser beam on a light receiving surface when the cantilever is displaced during measurement of properties of a sample is defined as a first direction, and a direction orthogonal to the first direction on the light receiving surface is defined as a second direction, the laser beam adjustment unit adjusts the laser beam such that a length of the spot of the laser beam in the second direction during adjustment of a position of a detection unit is longer than a length of the spot of the laser beam in the first direction during measurement of the properties of the sample.