A first vector predictor candidate list generating unit generates a first motion vector predictor candidate list from motion vectors of encoded neighboring blocks to blocks to be encoded. A second vector predictor candidate list generating unit generates a second motion vector predictor candidate list from motion vectors of blocks at the same positions as the blocks to be encoded in an encoded image and neighboring blocks to the blocks at the same positions. A combination determining unit determines whether to generate a third vector predictor candidate list combining the first and second vector predictor candidate lists by comparison of a block size of the blocks to be encoded and a threshold size. A vector predictor candidate list deciding unit generates the third vector predictor candidate list from the first vector predictor candidate list.