[Object] To improve detection precision of a subject at a lower cost. [Solution] Provided is an image processing device including: a plurality of detection units configured to detect respective detection regions indicating temperatures within mutually different setting temperature ranges from a far-infrared image； and a determination unit configured to determine whether a predetermined subject is shown in the far-infrared image on the basis of a positional relation between the plurality of detected detection regions and modeling which regulates the positional relation in a case in which the predetermined subject is shown in the far-infrared image.
