An inter-layer video decoding method comprising: determining a size of a subblock of a current block by comparing at least one of a height and a width of a predetermined minimum size of the subblock with at least one of a height and a width of the current block of a first layer image; determining at least one subblock from the current block according to the size of the subblock of the current block; determining a candidate block that corresponds to the current block and is comprised in an encoded second layer image; determining a candidate subblock from the candidate block of the second layer image by using the subblock of the current block; determining motion information of the subblock comprised in the current block by using motion information of the candidate subblock comprised in the candidate block; and generating a prediction block of the current block by using the motion information of the subblock comprised in the current block, characterized in that the determining of the size of the subblock of the current block by comparing at least one of the height and the width of the predetermined minimum size of the subblock with at least one of the height and the width of the current block of the first layer image comprises: when at least one of the height and the width of the current block is not an integer multiple of at least one of the height and the width of the predetermined minimum size of the subblock and one of the height and the width of the current block is smaller than the one of the height and the width of the predetermined minimum size of the subblock and the other one of the height and the width of the current block is greater than the other one of the height and the width of the predetermined minimum size of the subblock, determining the size of the subblock of the current block to be equal to the size of the current block, wherein the determining of the size of the subblock of the current block to be equal to the size of the current block comprises determining a height of the subblock of the current block to be equal to the height of the current block and determining a width of the subblock of the current block to be equal to a width of the current block. determining a size of a subblock of a current block by comparing at least one of a height and a width of a predetermined minimum size of the subblock with at least one of a height and a width of the current block of a first layer image; determining at least one subblock from the current block according to the size of the subblock of the current block; determining a candidate block that corresponds to the current block and is comprised in an encoded second layer image; determining a candidate subblock from the candidate block of the second layer image by using the subblock of the current block; determining motion information of the subblock comprised in the current block by using motion information of the candidate subblock comprised in the candidate block; and generating a prediction block of the current block by using the motion information of the subblock comprised in the current block, characterized in that the determining of the size of the subblock of the current block by comparing at least one of the height and the width of the predetermined minimum size of the subblock with at least one of the height and the width of the current block of the first layer image comprises: when at least one of the height and the width of the current block is not an integer multiple of at least one of the height and the width of the predetermined minimum size of the subblock and one of the height and the width of the current block is smaller than the one of the height and the width of the predetermined minimum size of the subblock and the other one of the height and the width of the current block is greater than the other one of the height and the width of the predetermined minimum size of the subblock, determining the size of the subblock of the current block to be equal to the size of the current block, wherein the determining of the size of the subblock of the current block to be equal to the size of the current block comprises determining a height of the subblock of the current block to be equal to the height of the current block and determining a width of the subblock of the current block to be equal to a width of the current block. when at least one of the height and the width of the current block is not an integer multiple of at least one of the height and the width of the predetermined minimum size of the subblock and one of the height and the width of the current block is smaller than the one of the height and the width of the predetermined minimum size of the subblock and the other one of the height and the width of the current block is greater than the other one of the height and the width of the predetermined minimum size of the subblock, determining the size of the subblock of the current block to be equal to the size of the current block, wherein the determining of the size of the subblock of the current block to be equal to the size of the current block comprises determining a height of the subblock of the current block to be equal to the height of the current block and determining a width of the subblock of the current block to be equal to a width of the current block.