An image processing apparatus (10) according to the present disclosure includes: a skeleton detection unit (11) configured to detect two-dimensional skeleton structures of a plurality of persons based on an acquired two-dimensional image; a feature calculation unit (12) configured to calculate features of the plurality of two-dimensional skeleton structures that have been detected by the skeleton detection unit (11); and a recognition unit (13) configured to perform processing of recognizing states of the plurality of persons based on a degree of similarity among the plurality of features that have been calculated by the feature calculation unit (12).