1. An image processing device comprising: a microcomputer operable to: calculate a plurality of motion vectors for each of a plurality of target blocks set up in a current target image, wherein the plurality of motion vectors are calculated by detecting a plurality of block positions corresponding to each of the plurality of target blocks in a search range set up in a current reference image, wherein the plurality of block positions are maximally correlated with each of the plurality of target blocks; calculate an inter-image motion vector between the current target image and the current reference image based on the plurality of motion vectors for each of the plurality of target blocks set up in the current target image; and set up a predictive motion vector for the current target image based on a plurality of inter-image motion vectors calculated between a plurality of target images and a plurality of reference images in further past than the current target image, wherein the search range is set up on the current reference image based on a position of a target block from the plurality of target blocks and the predictive motion vector.