1. An image processing method for creating a disparity image for a three-dimensional display from a two-dimensional video image, comprising: detecting, based on a first image of the two-dimensional video image in an arbitrary time and a second image in another time different from the first image, motion vectors between the first image and the second image for each block of the first image; detecting a most backward vector obtained for a block to be most backward from the motion vectors; calculating differential vectors between each motion vector and the most backward vector and giving a depth on a close to the block of the first image corresponding to the motion vector having the larger differential vector; and creating one or more disparity images from the first image and the depth.