CALIBRATION METHOD OF SURFACE QUALITY MEASURING MACHINE

PROBLEM TO BE SOLVED: To provide a calibration method of a surface quality measuring machine, which can accurately grasp mutual positional relations between an upward stylus and a downward stylus.SOLUTION: A calibration method of a surface quality measuring machine includes an X-axis shape measurement data acquisition step for acquiring X-axis upper shape measurement data by relatively moving a downward stylus in an X-axis direction while keeping it contacting to an upper surface of a reference sphere and also for acquiring X-axis lower shape measurement data by relatively moving an upward stylus in the X-axis direction while keeping it contacting to a lower surface of the reference sphere, and an offset amount calculation step for calculating offset amounts ΔX, ΔZ of the upward and downward styluses from central coordinates O3, O4 obtained by the X-axis shape measurement data acquisition step.