Coordinates of a first region extraction window, a first sample stage coordinate, a second sample stage coordinate, and a second region extraction window, including images of one sample stage and an observation target tissues of a sample when the one sample stage is respectively positioned on two microscopes are respectively obtained. Based on difference between the first sample stage coordinate and the second sample stage coordinate, the second sample stage coordinate is corrected. Based on the obtained corrected second sample stage coordinate, the second positioning unit is moved from the second non-observation position to the second observation position where the second region extraction window is located at a position corresponding to the coordinate position of the first region extraction window.