An image processing apparatus and an image processing method for processing far-infrared ray images are provided. Specific temperature ranges constituted by pixels having values falling within a temperature range characteristic of a specific target are extracted from a far-infrared ray image captured of the same target. Of the specific temperature ranges, those having motion vectors close to each other are integrated so as to generate integrated ranges. The integrated ranges having motion vectors close to a global motion vector indicative of the motion of the image as a whole are excluded to obtain excluded integrated ranges. Visible light ranges corresponding to the specific temperature ranges in the excluded integrated ranges are extracted from the visible light image to generate visible light motion ranges. The positions of the visible light motion ranges are corrected on the basis of the motion vector of the excluded integrated ranges as a whole.