There is provided a decoding apparatus and a decoding method which are for using compressed data efficiently by making the resolutions of the individual components differ from one another. A decoding apparatus decodes compressed data that represents an image signal composed of a plurality of components as a compressed code by making the resolutions of the individual components differ from one another. The decoding apparatus basically comprises input sections 5-Y, 5-I, 5-Q which decode compressed data and take in the individual components independently, a reduction circuit 5-Y-1 which reduces and changes a size corresponding to the processing unit and resolution of any one of the components, and a conversion section 5-6 which converts into a decoded image signal in a specific format by using reduced components and uncompressed components.