1. A moving picture decoding device that decodes a bitstream obtained by coding a moving picture using a motion vector in units of blocks obtained by partitioning each picture, comprising: a decoding unit that decodes information representing a motion vector predictor index to be selected in a motion vector predictor candidate list; a motion vector predictor candidate constructing unit that derives first and second motion vector predictor candidates from a motion vector of one of decoded blocks neighboring a decoding target block in a same picture as the decoding target block, and derives a third motion vector predictor candidate from a motion vector of one of blocks of a decoded picture different from the decoding target block; a motion vector predictor candidate adding unit that adds the first to third motion vector predictor candidates satisfying a certain condition to a motion vector predictor candidate list; a redundant motion vector predictor candidate determining unit that deletes the second motion vector predictor candidate from the motion vector predictor candidate list when the first and second motion vector predictor candidates added to the motion vector predictor candidate list by the motion vector predictor candidate adding unit have the same values; a motion vector predictor candidate limiting unit that repeatedly adds a motion vector predictor candidate having a same value to the motion vector predictor candidate list until the number of motion vector predictor candidates reaches a certain number when the number of the motion vector predictor candidates added to the motion vector predictor candidate list is smaller than the certain number (a natural number larger than or equal to 2); and a motion vector predictor selecting unit that selects a motion vector predictor of the decoding target block from the motion vector predictor candidate list based on the decoded information representing the motion vector predictor index to be selected, wherein the redundant motion vector predictor candidate determining unit does not compare the value of the first motion vector predictor candidate and the value of the second motion vector predictor candidate with the third motion vector predictor candidate.