1. A motion vector predicting method predicting a motion vector, in a macro block divided into plural small blocks, for reducing a prediction processing time for plural motion vectors of the macroblock, the method comprising: selecting at least one small block from the macro block which a motion vector can be predicted using motion vector information of at least one adjacent decoded small block of the macro block; and using a computer to simultaneously perform a motion vector prediction of the selected at least one small block with a separate motion vector prediction of another small block of the macro block, wherein a motion vector of the other small block can be predicted using motion vector information of the at least one adjacent decoded small block.