1. A video predictive encoding device comprising: a region division unit which divides an input picture into a plurality of regions; a predicted signal generation unit which determines a motion vector used to derive, from a previously-reproduced picture, a signal having a high correlation with a target region, the signal being derived as an encoding target out of the regions divided by the region division unit; a motion information storage which stores the motion vector; a residual signal generation unit which generates a residual signal between a predicted signal of the target region and a pixel signal of the target region; a residual signal compression unit which compresses the residual signal generated by the residual signal generation unit; a residual signal reconstruction unit which generates a reproduced residual signal by reconstruction from compressed data of the residual signal; an encoding unit which selects and encodes a motion vector predictor similar to a motion vector of the target region, the motion vector predictor selected from: previously-reproduced motion vectors stored in the motion information storage, side information determined from the motion vector of the target region, and the compressed data of the residual signal; and a picture storing unit which adds the predicted signal to the reproduced residual signal to reconstruct a pixel signal of the target region, and which stores the reconstructed pixel signal as the previously-reproduced picture, wherein the motion vector includes a zero-th motion vector used to generate a zero-th predicted signal, and a first motion vector used to generate a first predicted signal, and wherein the predicted signal generation unit comprises: a zero-th motion information estimation unit which estimates the zero-th motion vector used to generate the zero-th predicted signal, selects, from a plurality of motion vectors stored in the motion information storage, a zero-th motion vector predictor which is similar to the estimated zero-th motion vector, and generates zero-th side information containing a zero-th motion vector predictor index to identify the selected zero-th motion vector predictor, and a motion vector difference determined from the zero-th motion vector and the zero-th motion vector predictor; a first motion information estimation unit which: selects, from a plurality of motion vectors stored in the motion information storage, a motion vector having a high correlation with the target region for generation of the first predicted signal, generates first side information containing a first motion vector predictor index to identify the selected motion vector as a first motion vector predictor, and sets the first motion vector predictor as the first motion vector; and a predicted signal combining unit which combines the zero-th predicted signal and the first predicted signal to generate the predicted signal of the target region.