Provided is a co-movement-based automatic categorization method, which includes: receiving image data created by photographing a plurality of subjects; detecting movement data including information on subjects' behaviors from the image data; determining whether or not co-movement between the subjects has been done during each predetermined time interval, and generating co-movement clusters in synchronized time sections, and non-co-movement clusters in desynchronized time sections depending on results of determination; if the duration time of a co-movement cluster is shorter than a standard co-movement duration time, converting the co-movement cluster to a non-co-movement cluster; categorizing the co-movement clusters by grouping a plurality of co-movement clusters existing in the same timeslot into one group; and forming a social network with a co-movement cluster group or a single co-movement cluster, and issuing a social identification to the social network.