SUBJECT TRACKING DEVICE, SUBJECT TRACKING METHOD, AND CAMERA

PROBLEM TO BE SOLVED: To appropriately update a template image.SOLUTION: A subject tracking device 100 comprises: similarity calculation means 104a that sets a target image in an object image and calculates similarity between a labeling template image to be updated and the target image; subject position identification means 104a that identifies a subject position in the object image on the basis of the calculated similarity; subject estimation means 104a that estimates a centroid position of a subject and a size thereof in a subject candidate area set centering around the identified subject position; labeling template image update means 104a that updates the labeling template image to an image centering around the estimated centroid position on the basis of the object image; and reliability determination means 104a that determines the presence or absence of reliability of an estimation result by the subject position identification means 104a. When the reliability determination means 104a determines that the estimation result is reliable, the labeling template image is updated.