An animal blood cell measuring apparatus comprising: a specimen preparation section for preparing a measurement specimen from blood of an animal; a characteristic information obtaining section for obtaining characteristic information indicating a characteristic of the measurement specimen, from the measurement specimen prepared by the specimen preparation section; and a controller configured for performing operations comprising: (a) classifying aggregate reticulocytes contained in the blood from other blood cells, based on the characteristic information obtained by the characteristic information obtaining section; and (b) outputting information regarding a number of the classified aggregate reticulocytes.