It has been difficult to highly accurately measure the profiles of samples using scanning probe microscopes at the time when scanning is performed due to scanning mechanism fluctuations in the non drive direction, i.e., vertical direction. The present invention is provided with, on the rear side of a sample stage, a high-accuracy displacement gauge for measuring fluctuation in the non drive direction, i.e., vertical direction, at the time when the sample stage is being scanned in the horizontal directions, and as a result, highly accurate planarity evaluation with accuracy of sample nm-order or less is made possible by correcting sample surface shape measurement results obtained using a probe.