1. A video encoder comprising: a motion estimation unit which generates a current block and a motion vector of each of a plurality of neighboring partitions around the current block; a motion vector estimation unit which selects at least one of partitions, which are compared with the current block for obtaining a motion vector difference, from among a plurality of neighboring partitions around the current block based on the spatial similarities between the current block and the plurality of neighboring partitions, estimates a motion vector of the selected partition as the motion vector of the current block, generates the motion vector difference, and transmits information on the motion vector difference and partition information for reconstruction of the motion vector of the current block; and an entropy-coding unit which performs entropy-coding on the information on the motion vector difference and the partition information for reconstruction of the motion vector of the current block.