Provided is an inter prediction method including determining a collocated block of a current block of a current image from among blocks of an image that is restored prior to the current image; preferentially checking whether a first reference list from among reference lists of the collocated block is referred to and selectively checking whether a second reference list is referred to according to whether the first reference list is referred to; based on a result of the checking, determining a single collocated reference list from among the first reference list and the second reference list; determining a reference block of the current block by using motion information of the collocated reference list; and performing inter prediction on the current block by using the determined reference block.