A control apparatus includes a detection unit, an association unit, and an output control unit. The detection unit detects a person from an image which includes a plurality of persons. The association unit associates the persons included in the image with each other based on at least one of a position of the person detected by the detection unit, directions of faces of the persons included in the image, and distances between the persons included in the image. The output control unit causes an output unit to output information that is indicative of a relation of the detected person with respect to other persons included in the image based on a result of association performed by the association unit.