The present invention provides a calculation method of calculating a shape of a measurement target surface, including a step of obtaining first corrected shape data by correcting first shape measurement data by using a first correction parameter for correcting a measurement error caused by scanning a probe in a first direction, obtaining second corrected shape data by correcting second shape measurement data by using a second correction parameter for correcting a measurement error caused by scanning the probe in a second direction, and generating first whole shape data representing a shape of the whole measurement target surface by synthesizing the first corrected shape data and the second corrected shape data.