A photographing control unit comprising a drive signal generator, an analog front end, a synchronization signal generation unit, and a system control unit controls an imager under a predetermined photographing condition, so that the imager photographs an observation image of a sample observed by a microscope and formed on a light receiving surface of the imager. A computing unit obtains inputs of a plurality of photographing parameters, determines a photographing condition based on the obtained photographing parameters, and sets the photographing condition for the photographing control unit. A display unit displays the designable ranges of the photographing parameters. Here, when the computing unit obtains the input of a priority parameter, it changes the designable range of the plurality of photographing parameters other than the priority parameter based on the priority parameter and causes the display unit to display the designable range after the change.