1. A video encoding method for encoding a video image by dividing an entire image into areas, generating a predicted image for each area of the divided image based on image information of a plurality of already-encoded frames, and encoding differential information between an image of an encoding target area in an encoding target frame and the predicted image, the video encoding method comprising: a reference vector target frame selecting step of selecting a reference vector target frame from among the already-encoded frames; a reference vector target frame designation information encoding step of encoding information which designates the reference vector target frame; a reference vector setting step of setting a reference vector which indicates an area which belongs to the reference vector target frame and corresponds to the encoding target area; a reference vector encoding step of encoding the reference vector; a reference frame selecting step of selecting a reference frame from among the already-encoded frames; a reference frame designation information encoding step of encoding information which designates the reference frame; a reference frame area setting step of searching for a corresponding area by using the reference frame and image information of the reference vector target area which belongs to the reference vector target frame and is indicated by the reference vector; and setting a reference area in the reference frame based on the search result; a predicted image generating step of generating the predicted image by using image information of the reference frame, which corresponds to the reference area; and a differential information encoding step of encoding differential information between image information of the encoding target area and the generated predicted image.