A method of video decoding, the method comprising: receiving prediction information on an inter prediction applied to a current block; determining a prediction mode to be applied to the current block based on the prediction information; and performing the inter prediction on the current block with the determined prediction mode, wherein, in the step of performing the inter prediction, to derive motion information on the current block, candidate blocks used for a merge mode are searched in a region in which candidate blocks used for a mode using motion vector predictor, hereafter referred to as AMVP mode, are searched, wherein the merge mode is an inter prediction mode in which a motion vector of a candidate block for the merge mode is used as a motion vector of the current block, wherein the AMVP mode is an inter prediction mode in which a motion vector of a candidate block for the AMVP mode is used as the motion vector predictor for the current block, wherein the prediction information includes a merge flag indicating whether the merge mode is applied to the current block, wherein the prediction information includes index information indicating the candidate block for the merge mode on the current block among the candidate blocks when it is determined that the merge mode is applied to the current block, characterized in that: the candidate blocks used for the merge mode and for the AMVP mode include a first block positioned at the left side of the current block, a second block positioned at the top side of the current block, a third block positioned at the bottom left corner of the current block, a fourth block positioned at the top right corner of the current block, a fifth block positioned at the top left corner of the current block and a co-located block of the current block in a reference picture. receiving prediction information on an inter prediction applied to a current block; determining a prediction mode to be applied to the current block based on the prediction information; and performing the inter prediction on the current block with the determined prediction mode, wherein, in the step of performing the inter prediction, to derive motion information on the current block, candidate blocks used for a merge mode are searched in a region in which candidate blocks used for a mode using motion vector predictor, hereafter referred to as AMVP mode, are searched, wherein the merge mode is an inter prediction mode in which a motion vector of a candidate block for the merge mode is used as a motion vector of the current block, wherein the AMVP mode is an inter prediction mode in which a motion vector of a candidate block for the AMVP mode is used as the motion vector predictor for the current block, wherein the prediction information includes a merge flag indicating whether the merge mode is applied to the current block, wherein the prediction information includes index information indicating the candidate block for the merge mode on the current block among the candidate blocks when it is determined that the merge mode is applied to the current block, characterized in that: the candidate blocks used for the merge mode and for the AMVP mode include a first block positioned at the left side of the current block, a second block positioned at the top side of the current block, a third block positioned at the bottom left corner of the current block, a fourth block positioned at the top right corner of the current block, a fifth block positioned at the top left corner of the current block and a co-located block of the current block in a reference picture.