<p>Provided is an image encoding method for deriving prediction motion vectors which is adapted to improve motion vector-encoding efficiency. The image encoding method encodes a block to be encoded by making predictions using a first motion vector designating a position within a first reference picture included in a first reference picture list and a second motion vector designating a position within a second reference picture included in a second reference picture list, and includes an addition step for adding the first motion vector as a candidate prediction motion vector to a candidate list of prediction motion vectors for use in the encryption of the second motion vector, a selection step for selecting the prediction motion vector to be used to encode the second motion vector from the candidate list including the first motion vector, and an encoding step for encoding the second motion vector using the selected prediction motion vector.</p>
