A prediction mode is selected in accordance with a type of a moving picture. When an interframe prediction mode is selected as the prediction mode, a motion vector for the moving picture is detected. Motion compensation for the moving picture is performed based on the type of the moving picture, the prediction mode, and the motion vector. A spatial prediction section performs a spatial prediction for the moving picture based on the type of the moving picture and the prediction mode. An orthogonal transformation for a predictive residue signal obtained as a difference between the picture signal obtained by the motion compensation or the spatial prediction and the input picture signal is performed, based on the type of the moving picture and the prediction mode. Variable length encoding for the picture data after the orthogonal transformation is performed, based on the type of the moving picture and the prediction mode.