A coding apparatus for hierarchically (layered data) coding two field data associated with each of a plurality of picture data composing a moving picture image. The coding apparatus comprising: a first coding unit configured to encode one of the two field data; a conversion unit configured to interpolate first predicted image data generated by the first coding unit encoding the one of the two field data and generate second predicted image data of a scanning position of the other field data of the two field data; and a second coding unit configured to encode the other field data of the two field data based on the second predicted image data generated by the conversion unit.