Techniques for specifying an observing or working position of a sample are provided. Digitized data of a sample is obtained and stored in a 1st storage device. A 1st display area displays an image of a portion containing a desired observing or working position of the digitized data stored in the 1st storage device. A 1st position that is indicated by a pointing device on the 1st display area is stored in a 2nd storage device. The sample is moved to an observing or working position for observation, and an observation image of the sample is stored in the 3rd storage device. A 2nd display area displays the observation image of the sample stored in the 3rd storage device. A position indicated on the 2nd display area and corresponding to the 1st position stored in the 2nd storage device is stored in a 4th storage device. A conversion function for converting a coordinate system of the 1st display area and the 2nd display area is calculated using the 1st position stored in the 2nd storage means and the position stored in the 4th storage device. A position indicated in one of the 1st and 2nd display areas and corresponding to another position indicated in the other of the 1st and 2nd display areas is calculated in accordance with the calculated conversion function.