An observation device, comprising an image sensor that forms an image of a specimen, and a processor having a focus control section and an analyzer, wherein the focus control section, in a case where image data for analysis of the specimen by the analyzer is obtained when a plurality of maximum values have been generated for change in contrast evaluation value corresponding to change in the focus position, controls focus position any focus position that corresponds to the plurality of maximum values, and the image sensor outputs image data that has been imaged.