1. A motion vector decoding method for decoding a coded motion vector of a current block in a moving picture, comprising: specifying a three neighboring block blocks which is are located in a neighborhood of the current block and is are previously decoded; deriving a predictive motion vector of the current block; and decoding the coded motion vector of the current block using the predictive motion vector ; to derive a final motion vector of the current block, wherein deriving the final motion vector of the current block comprises: adding the predictive motion vector of the current block to a decoded difference motion vector of the current block to derive the final motion vector of the current block, wherein, in the deriving of the predictive motion vector of the current block , when comprises: responsive to determining that at least one of the three neighboring block blocks is decoded based on a motion vector of another block coded in a skip mode or a direct mode , deriving the predictive motion vector of the current block is derived based on the a motion vector of the another block different from the three neighboring blocks, and responsive to determining that none of the three neighboring blocks are coded in the skip mode or the direct mode, deriving the predictive motion vector of the current block based on one or more motion vectors of the three neighboring blocks .