A temperature-controlled room accommodates an incubation container incubating a sample and maintains the inside thereof in a predetermined environment condition. An imaging section generates data of a plurality of observing images. An image analyzing section performs an image analyzing process on the data of the plurality of observing images obtained by imaging the incubation container at different times. Image analyzing data generated by the image analyzing section includes morphological information which indicates incubation states of the samples and rate-of-change information regarding the morphological information. A search processing section conducts a search for the incubation container which meets the first searching condition and the second searching condition based on the image analyzing data.