According to a picture coding method of the present invention, a coded picture identified by a picture number is stored, as a reference picture, into a storage unit; commands indicating correspondencebetween picture numbers and reference indices for designating reference pictures and coefficients used for generation of predictive images are generated; a reference picture being used when motion compensation is performed on a current block in a current picture to be coded is designated by a reference index; a predictive image is generated by performing linear prediction on a block being obtained by motion estimation within the designated reference picture, by use of a coefficient corresponding to the reference index; a coded image signal including a coded signal obtained by coding a prediction error being a difference between the current block in the current picture to be coded and the predictive image, the commands, the reference index and the coefficient is outputted. At that time, information indicating the maximum reference index value is coded and included into the coded image signal, and the commands indicating correspondence between at least one picture number and a pluralityof reference indices are generated.