A method of decoding motion information according to an embodiment includes: obtaining information indicating a disparity distance for determining a prediction motion vector of a current block; scaling the disparity distance corresponding to the obtained information, based on a comparison result between a base pixel unit and a smallest pixel unit indicatable by a motion vector of the current block; determining a prediction motion vector candidate changed by the scaled disparity distance from a base motion vector of the current block from among one or more prediction motion vector candidates as the prediction motion vector of the current block; and determining the motion vector of the current block by using the prediction motion vector.