An image decoding apparatus includes an analyzing section and an image decoding section. The analyzing section determines a process quantity of a coded image data to each of a plurality of image decoding processes within a unit process time based on a parameter of the coded image data, prior to the plurality of image decoding processes. The image decoding section carries out each of the plurality of image decoding processes to the coded image data for the determined process quantity such that a decoded image data is generated from the coded image data.