An object of the present invention is to provide an image decompression apparatus, a medium recording an image decompression program, and an image decompression method capable of sequentially decompressing compressed data of a plurality of images. An image decompression apparatus includes: a request frame number acquisition section that sequentially acquires request frame numbers which are the numbers assigned to frames for which decompression is required in the forward or backward direction of the frame number a compressed data acquisition section that acquires compressed data of a first compression unit to which the request frame number belongs and compressed data of a second compression unit adjacent to the first compression unit in the backward direction of the frame number a decompression section that decompresses the compressed data of the first and second compression units acquired by the compressed data acquisition section to obtain decompressed images and an image holding section that holds the decompressed images of the first and second compression units generated by the decompression section and extracts decompressed image corresponding to the request frame numbers so as to output the decompressed images.
