A receiving processing unit receives identical SD pictures transmitted a plurality of number of times, and performs addition for weighting an SD picture stored in a storage and the received SD pictures. The receiving processing unit stores the obtained values as a new SD picture in the storage. A picture-quality determining unit determines the picture quality of the new SD picture stored in the storage, and based on the determined picture quality, a request-signal transmitting unit requests class codes representing classes obtained by classifying the pixels of an HD picture in which the quality of an SD picture is increased. A receiving-control unit receives class codes which are transmitted in response to the request, and based on the SD picture and the class codes, an adaptive processing unit calculates predicted values of an HD picture corresponding to the SD picture.