1. A method for predictive encoding a motion vector used in motion compensated prediction of a video sequence consisting of a temporal sequence of frame pictures, the method comprising: a step of determining a motion vector of a target partition in a frame picture of an encoding target in the video sequence; a step of determining a first motion vector predictor candidate that satisfies a predetermined criterion used in determination of motion vector predictor candidates, the first motion vector predictor candidate determined from a motion vector or motion vectors of one or more partitions belonging to a left-neighboring region located on a left side of the target partition; a step of determining a second motion vector predictor candidate that satisfies the predetermined criterion used in determination of motion vector predictor candidates, the second motion vector predictor candidate determined from a motion vector or motion vectors of one or more partitions belonging to an above-neighboring region located above the target partition; a step of selecting an optimum motion vector predictor and outputting motion vector predictor indication information to specify the selected optimum motion vector predictor, wherein the optimum motion vector predictor is selected based on comparison between one or more motion vector predictor candidates including the first motion vector predictor candidate and the second motion vector predictor candidate, and the motion vector of the target partition; and a step of encoding the motion vector predictor indication information.