A decoding method for decoding a coded image signal predictively a signal moving image composed of a plurality of pictures, said encoded picture signal an encoded image is encoded according to an encoding rule by which an image which has encoded can refer to a previous reference image to an image passing reference is the latest in a display order default to display the decoded pictures, comprising: decoding the coded image signal to obtain a decoded picture, deciding (602) whether the decoded picture is a reference picture or an image that is reference on the basis of the coded image signal, being a reference image an image which is being referred to in predictive encoding by another picture and being an image that is a reference image that is not subject to referred to in predictive encoding by another picture, and storing (606), in the case where the decoded picture is a reference picture, the decoded picture in a buffer, characterized by: judging (603), in the case where the decoded picture is a picture that is not the reference, if it can be displayed or not the decoded picture is not a reference, according to said predetermined display order, prior to all images decoded currently stored in the buffer, and storing (604 ), in the case where it can not display the decoded picture is not a reference, according to said predetermined display order, prior to all images decoded currently stored in the buffer, the decoded picture is no reference in the buffer without outputting the decoded picture is not a reference, wherein, when the buffer does not have an empty space pair to the decoded picture is not a reference, the decoded picture is no reference in the buffer after obtaining an empty space by removing (605) the decoded picture stored in the buffer with the display order is stored more advance and will not be used for reference after the decoding of the decoded image that is not a reference.