To measure surface information and physical information of a sample with
high accuracy by promoting linearity in Z direction by nullifying cross
talk in XY directions as less as possible, there is provided a surface
information measuring apparatus including a probe having a stylus, a Z
actuator fixed with the probe for being elongated and contracted in Z
direction orthogonal to a sample surface B when applied with a voltage,
an applicator for applying the voltage to the Z actuator, and a
controller for controlling to operate the applicator, in which the Z
actuator includes a piezoelectric member capable of being elongated and
contracted in Z direction and a plurality of divided electrodes provided
to be respectively electrically independent from each other in a state of
being divided by at least 3 or more in a peripheral direction at an inner
peripheral face or an outer peripheral face of the piezoelectric member
for applying voltages to elongate and contract the piezoelectric member
within ranges of contact regions, and the controller controls the
applicator to apply voltages by a previously determined rates of voltage
applying amounts such that elongating or contracting amounts of
respective contact regions of the piezoelectric member respectively
brought into contact with the divided electrodes respectively become the
same.