A coding apparatus derives a first candidate having a first motion vector that has been used to code a first block, a second candidate having a second motion vector that is a first zero vector, and a third candidate having a third motion vector that is a second zero vector. The coding apparatus selects one candidate from candidates including the first, second, and third candidates, and codes an index identifying the selected candidate. A decoding apparatus derives a fourth candidate having a fourth motion vector that has been used to decode the first block, a fifth candidate having a fifth motion vector that is a third zero vector, and a sixth candidate having a sixth motion vector that is a fourth zero vector. The decoding apparatus derives an index identifying one candidate from candidates including the fourth, fifth, and sixth candidates, and selects the candidate identified by the index.