An unit for switchable arranging an arbitrary optical element on an optical path of fluorescence from among a plurality of types of the optical elements that transmit an excitation beam for exciting a sample and fluorescence emitted from the sample; an unit for picking up the observation image via the optical element arranged; and an unit for determining a type of the optical element arranged on the basis of the observation image picked up are prepared in order to provide a microscope image processing device, a program product, a program transmission medium and a method are provided, by which an optical element such as a fluorescence cube set on a fluorescence microscope can be identified on the basis of a detection result of an image pick up device that picks up an image of a sample to be observed by using the fluorescence microscope.