Image encoding/decoding device and method, and reference picture indexing device and method

Disclosed are an image encoding/decoding device and method, and a reference picture indexing device and method. According to an embodiment of the present invention, the reference picture indexing device which indexes a reference picture in order to estimate a motion vector comprises: a candidate reference picture setup unit which sets candidates of reference pictures; a priority determination unit which determines priority in accordance with a block that is currently being encoded, relative to the candidates of the reference pictures set by the candidate reference picture setup unit; and a reference picture indexing unit which adaptively indexes the reference pictures according to the block that is currently being encoded, on the basis of the priority determined by the priority determination unit.