1. A method of estimating a motion vector of a current block, the method comprising: selecting at least one 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 spatial similarities between the current block and the plurality of neighboring partitions; estimating a motion vector of the selected partition as the motion vector of the current block and generating the motion vector difference; and transmitting information on the motion vector difference and partition information for reconstruction of the motion vector of the current block, wherein the spatial similarities are obtained based on an average value of pixels of the current block and an average value of pixels of each of the neighboring partitions.