To provide an image encoding apparatus capable of reducing memory capacity to be used, the amount of image data to be transferred, and inter-block differential computational quantity.

The present invention relates to an image encoding apparatus that divides a picture of a moving image into blocks of a prescribed size and refers to reference pictures stored in a reference image memory for each divided block to perform motion compensation predictive encoding of the picture of the moving image, including: a reading means for reading from the reference image memory a block of the reference pictures corresponding to a block of the pictures of the moving image; an index value calculating means for calculating an index value by comparing the block of the pictures of the moving image with the block of the reference pictures read by the reading means; and a storage means for storing the block of the pictures of the moving image in the reference image memory on the basis of the index value calculated by the index value calculating means.