An image decoding apparatus which decodes externally received encoded image information includes a storage unit which stores the image information. The image decoding apparatus includes a first decoding unit which receives, from the storage unit, image data to be decoded and reference data, and decodes the target image data. The image decoding apparatus includes a second decoding unit which receives the image data decoded by the first decoding unit, receives, from the storage unit, image data to be decoded based on the decoded image data, and decodes the image data received from the storage unit. The image decoding apparatus includes a decoding control unit which controls the first and second decoding units to repetitively execute decoding of image data in parallel.