It is possible to reliably and efficiently determine whether a specimen contains viruses, bacteria, etc. and, if it does, identify their types, regardless of the observer. Furthermore, even a newly-discovered bacterium can be quickly identified by utilizing a database at a remote location. A transmission microscope system has a microscope for observing a specimen and a database which stores, for each microscopic thing (such as a virus), a name, a specimen pretreatment method and an imaging condition used when the microscopic thing is observed, captured image data, etc. An image of the specimen is captured according to a specimen pretreatment method and an imaging condition retrieved from the database using the name of a target microscopic thing as a key, and the captured image is compared with images stored in the database to identify microscopic things present in the specimen.