A decoding device decodes coded image data having a plurality of color components and includes a variable length decoding unit that performs variable length decoding on the coded image data to generate variable length decoded data. A separation unit separates the plurality of color components to a predetermined number of color components, and obtains, from the variable length decoded data generated by the variable length decoding unit, each of pieces of data to be decoded in decoding processes, as necessary data required in at least one of decoding processes, and the decoding processes each corresponding to a corresponding component of the predetermined number of color components. Each of the image reconstruction units corresponds to a corresponding component of the predetermined number of color components, and generates, in parallel, decoded images regarding the respective components using the necessary data obtained by the separation unit.