A device and a process to count a number of colonies present in a set of samples. The colony counting device has a storage device with plural storage locations. A handling system is operative to convey samples to analyze from storage locations to an analysis area and from the analysis area to storage locations. An imaging device is operative to acquire a plurality of images of a sample to analyze, the plurality of images including all or a part of the analysis area. A processing unit is operative to implement, for each sample to analyze, a detection step to detect the presence of colonies by analyzing an image of the plurality of images of the sample and a determination step to determine the number of colonies present in the sample by counting the colonies whose presence have been detected during the detection step.