1. A moving picture coding device adapted to code moving pictures in units of blocks obtained by partitioning each picture of the moving pictures, comprising: a motion vector predictor candidate generation unit configured to derive one or more motion vector predictor candidates from motion vectors of coded prediction blocks neighboring a prediction block subject to coding within the same picture as the prediction block subject to coding, and to add the derived motion vector predictor candidates in a motion vector predictor candidate list; a motion vector predictor selection unit configured to select a motion vector predictor from the motion vector predictor candidate list; a motion vector difference derivation unit configured to derive a motion vector difference by subtracting the selected motion vector predictor from the motion vector; and a coding unit configured to code index information indicating the motion vector predictor candidate selected in the motion vector predictor candidate list and the motion vector difference, wherein the motion vector predictor candidate generation unit determines, for the purpose of obtaining a predetermined number of motion vector predictor candidates, which of the coded prediction blocks provides the motion vector from which to derive the motion vector predictor candidate, such that the motion vector predictor candidate generation unit processes, in a predetermined order, prediction blocks in a block group neighboring to the left and in a block group neighboring above, said processing being done according to conditions 1 and 2 below in the stated order and then according to conditions 3 and 4 below in the stated order, condition 1: there is found a motion vector that is predicted by using the same reference list and the same reference picture as that of the motion vector predictor subject to derivation in the prediction block subject to coding; condition 2: there is found a motion vector that is predicted by using a reference list different from that of the motion vector predictor subject to derivation in the prediction block subject to coding and using the same reference picture as that of the motion vector predictor subject to derivation in the prediction block subject to coding; condition 3: there is found a motion vector that is predicted by using the same reference list as that of the motion vector predictor subject to derivation in the prediction block subject to coding and using a reference picture different from that of the motion vector predictor subject to derivation in the prediction block subject to coding; and condition 4: there is found a motion vector that is predicted by using a reference list different from that of the motion vector predictor subject to derivation in the prediction block subject to coding and using a reference picture different from that of the motion vector predictor subject to derivation in the prediction block subject to coding.