A picture decoding method for decoding a bit stream of a coded picture signal, the picture decoding method comprising: decoding a bit stream of a coded picture signal to obtain: commands that indicate correspondence between reference indices and reference pictures; information that indicates a maximum reference index value; a plurality of weighting coefficient sets used for generating a predictive image; a reference index that identifies a reference picture for a decoding target block; and a prediction error; designating, based on the commands and the reference index, a reference picture which is referred to when the decoding target block is decoded through motion compensation; specifying a weighting coefficient set corresponding to the reference index, from among the plurality of weighting coefficient sets; generating the predictive image by performing linear prediction, using the specified weighting coefficient set, on pixel values of a reference block obtained from the reference picture designated in said designating; and generating a reconstructed image from the predictive image and the prediction error, wherein each of the plurality of weighting coefficient sets is specified by a corresponding one of the plurality of reference indices, wherein, in said specifying, a weighting coefficient set corresponding to the reference index which is obtained through decoding the decoding target block, from among the at least two weighting coefficient sets, is specified, and characterized in that at least two reference indices among the plurality of reference indices are assigned to one reference picture in the commands, and at least two weighting coefficient sets among the plurality of weighting coefficient sets are assigned to said one reference picture through said at least two reference indices. decoding a bit stream of a coded picture signal to obtain: commands that indicate correspondence between reference indices and reference pictures; information that indicates a maximum reference index value; a plurality of weighting coefficient sets used for generating a predictive image; a reference index that identifies a reference picture for a decoding target block; and a prediction error; designating, based on the commands and the reference index, a reference picture which is referred to when the decoding target block is decoded through motion compensation; specifying a weighting coefficient set corresponding to the reference index, from among the plurality of weighting coefficient sets; generating the predictive image by performing linear prediction, using the specified weighting coefficient set, on pixel values of a reference block obtained from the reference picture designated in said designating; and generating a reconstructed image from the predictive image and the prediction error, wherein each of the plurality of weighting coefficient sets is specified by a corresponding one of the plurality of reference indices, wherein, in said specifying, a weighting coefficient set corresponding to the reference index which is obtained through decoding the decoding target block, from among the at least two weighting coefficient sets, is specified, and characterized in that at least two reference indices among the plurality of reference indices are assigned to one reference picture in the commands, and at least two weighting coefficient sets among the plurality of weighting coefficient sets are assigned to said one reference picture through said at least two reference indices.