A motion vector predictor candidate constructing unit performs prediction based on a motion vector of one of coded blocks neighboring a coding target block in the same picture as the coding target block, constructs a plurality of motion vector predictor candidates, and adds the motion vector predictor candidates to a motion vector predictor candidate list. A motion vector predictor candidate number limiting unit limits the number of motion vector predictor candidates added to the motion vector predictor candidate list to a maximum candidate number according to a size of a prediction block. A motion vector predictor selecting unit selects a motion vector predictor from the motion vector predictor candidate list. A coding unit codes information representing an index of the selected motion vector predictor in the motion vector predictor candidate list.