To enable an uneven shape corresponding to an interest region extracted from two-dimensional distribution of another physical quantity to easily and correctly be understood in a two-dimensional distribution image of a height of predetermined range obtained with an SPM (scanning probe microscope).

An interest region is extracted by determining a threshold of data values forming an object image (two-dimensional or three-dimensional) from which the interest region is extracted (S5). The position information corresponding to the extracted interest region is acquired (S6), the display of a range corresponding to the position information is maintained as it is on an observation image (two-dimensional distribution image of height) and luminance of display outside the range is reduced to highlight and display the range of interest region (S7). In this way, color information of an original observation image is maintained as it is, differently from the case where two images are superimposed, and the uneven shape is displayed by optimal coloring.