A surface-profile measuring instrument includes a movement-estimating unit that estimates a movement state of a drive mechanism in accordance with a scanning vector command issued by a scanning vector commanding unit to calculate an estimated movement state quantity, and a correction calculating unit that corrects a detection value of a drive sensor in accordance with the estimated movement state quantity calculated by the movement-estimating unit. The movement-estimating unit has a nominal model setting unit in which a nominal model from the scanning vector commanding unit to the probe is set. The correction calculating unit includes a correction-amount calculating unit that calculates a correction amount for correcting a measurement error generated by a deformation of the drive mechanism in accordance with the movement thereof and a measurement data synthesizing unit that synthesizes the detection value of the drive sensor and the displacement sensor and the calculated correction-amount calculated by the correction-amount calculating unit.