A coding method for coding each of plural pictures constituting a moving image, said coding method comprising: a first and second information generating step of generating, on a picture-by-picture basis, either of (i) first information indicating that a target picture, which is one of an I picture, a P picture, and B picture, can be a reference picture to be referred to when coding at least one of P pictures following the target picture or coding at least one of B pictures following the target picture and (ii) second information indicating that the target picture cannot be a reference picture to be referred to when coding each of P pictures following the target picture or coding each of B pictures following the target picture; a third information generating step of generating, on a picture-by-picture basis, (iii) third information indicating a plurality of candidate reference pictures, each of the candidate reference pictures being a candidate for a reference picture selected from among pictures for which only the first information is attached, when coding a target P picture or coding a target B picture; a fourth information generating step of generating, on a block-by-block basis, (iv) fourth information indicating one specified reference picture to be referred to when performing predictive coding on a target block included in the target P picture or indicating one or two specified reference pictures to be referred to when performing predictive coding on a target block included in the target B picture; a storing step of storing, on a picture-by-picture basis, the target picture into a memory as a candidate reference picture only when the first information is generated for the target picture by the first and second information generating step; a coding step of coding, on a block-by-block basis, the target block by using the one specified reference picture when performing predictive coding on the target block included in the target P picture or by using the one or two specified reference pictures to be referred to when performing predictive coding on the target block included in the target B picture to generate coded block data; and, a bit stream generating step of generating a bit stream corresponding to the moving picture, by adding the first information, the second information, the third information and the fourth information to the coded block data, wherein said one specified reference picture is specified on a block-by-block basis, from among a plurality of candidate reference pictures which are stored in the memory, and the target block is predictively coded with reference to the one specified reference picture when performing predictive coding on the target block included in the target P picture, and wherein said one or two specified reference pictures are specified, on a block-by-block basis, from among a plurality of candidate reference pictures which are stored in the memory, and the target block is predictively coded with reference to the one or two specified reference pictures when performing predictive coding on the target block included in the target B picture. a first and second information generating step of generating, on a picture-by-picture basis, either of (i) first information indicating that a target picture, which is one of an I picture, a P picture, and B picture, can be a reference picture to be referred to when coding at least one of P pictures following the target picture or coding at least one of B pictures following the target picture and (ii) second information indicating that the target picture cannot be a reference picture to be referred to when coding each of P pictures following the target picture or coding each of B pictures following the target picture; a third information generating step of generating, on a picture-by-picture basis, (iii) third information indicating a plurality of candidate reference pictures, each of the candidate reference pictures being a candidate for a reference picture selected from among pictures for which only the first information is attached, when coding a target P picture or coding a target B picture; a fourth information generating step of generating, on a block-by-block basis, (iv) fourth information indicating one specified reference picture to be referred to when performing predictive coding on a target block included in the target P picture or indicating one or two specified reference pictures to be referred to when performing predictive coding on a target block included in the target B picture; a storing step of storing, on a picture-by-picture basis, the target picture into a memory as a candidate reference picture only when the first information is generated for the target picture by the first and second information generating step; a coding step of coding, on a block-by-block basis, the target block by using the one specified reference picture when performing predictive coding on the target block included in the target P picture or by using the one or two specified reference pictures to be referred to when performing predictive coding on the target block included in the target B picture to generate coded block data; and, a bit stream generating step of generating a bit stream corresponding to the moving picture, by adding the first information, the second information, the third information and the fourth information to the coded block data,