A motion estimator (150) for generating an interpolation frame based on current and previous frames is provided. The motion estimator includes: a first candidate motion vector calculating unit (10) which divides the current frame into plural blocks and generates plural first candidate motion vector groups, each group including a first candidate motion vector for each of the blocks calculated based on a previous motion vector previously estimated; a second candidate motion vector calculating unit (30) which calculates plural second candidate motion vectors for each of the blocks, each of the second candidate motion vectors being calculated based on a respective first candidate motion vector included in each of the first candidate motion vector group; and a final motion vector deciding unit (50) which selects a final motion vector for each of the blocks from among the second candidate motion vectors, the interpolation frame being generated based on the final motion vector.
