An automatic application system comprising automatic peeling apparatus and delivery slip label adherable to a delivery item and comprising: a belt-shaped mount sheet main body; a label main body, a reverse face of which being removably adhered to an obverse face of the mount sheet main body, and the label main body configured to be capable of being peeled off from the mount sheet main body and adherable to the delivery item, wherein: in the mount sheet main body, a re-peeling mount sheet region (22,23,24) is formed in a portion thereof that is more inward than an outer circumferential edge portion of the label main body so as to be separable from the mount sheet main body by a mount sheet separating cutting line, and in the label main body, a re-applying label region is formed separably in an upper layer portion of the re-peeling mount sheet region (22,23,24) so as to have a smaller area than the re-peeling mount sheet region (22,23,24); the label main body is configured to be capable of being peeled off from the mount sheet main body together with the re-applying label region by the automatic peeling apparatus while the re-peeling mount sheet region (22,23,24) of the mount sheet main body is kept removably adhered to the reverse face of the label main body and configured to be adherable to the delivery item; the re-applying label region of the label main body is configured to be capable of being peeled off from the re-peeling mount sheet region (22,23,24) of the mount sheet main body by the automatic peeling apparatus and adherable to a location other than the label main body on the delivery item; and the re-peeling mount sheet region (22,23,24) is configured to have a tapered shape toward an upstream side of a transfer direction of the delivery slip label in the automatic peeling apparatus in which the delivery slip label is to be loaded. a belt-shaped mount sheet main body; a label main body, a reverse face of which being removably adhered to an obverse face of the mount sheet main body, and the label main body configured to be capable of being peeled off from the mount sheet main body and adherable to the delivery item, wherein: in the mount sheet main body, a re-peeling mount sheet region (22,23,24) is formed in a portion thereof that is more inward than an outer circumferential edge portion of the label main body so as to be separable from the mount sheet main body by a mount sheet separating cutting line, and in the label main body, a re-applying label region is formed separably in an upper layer portion of the re-peeling mount sheet region (22,23,24) so as to have a smaller area than the re-peeling mount sheet region (22,23,24); the label main body is configured to be capable of being peeled off from the mount sheet main body together with the re-applying label region by the automatic peeling apparatus while the re-peeling mount sheet region (22,23,24) of the mount sheet main body is kept removably adhered to the reverse face of the label main body and configured to be adherable to the delivery item; the re-applying label region of the label main body is configured to be capable of being peeled off from the re-peeling mount sheet region (22,23,24) of the mount sheet main body by the automatic peeling apparatus and adherable to a location other than the label main body on the delivery item; and the re-peeling mount sheet region (22,23,24) is configured to have a tapered shape toward an upstream side of a transfer direction of the delivery slip label in the automatic peeling apparatus in which the delivery slip label is to be loaded. in the mount sheet main body, a re-peeling mount sheet region (22,23,24) is formed in a portion thereof that is more inward than an outer circumferential edge portion of the label main body so as to be separable from the mount sheet main body by a mount sheet separating cutting line, and in the label main body, a re-applying label region is formed separably in an upper layer portion of the re-peeling mount sheet region (22,23,24) so as to have a smaller area than the re-peeling mount sheet region (22,23,24); the label main body is configured to be capable of being peeled off from the mount sheet main body together with the re-applying label region by the automatic peeling apparatus while the re-peeling mount sheet region (22,23,24) of the mount sheet main body is kept removably adhered to the reverse face of the label main body and configured to be adherable to the delivery item; the re-applying label region of the label main body is configured to be capable of being peeled off from the re-peeling mount sheet region (22,23,24) of the mount sheet main body by the automatic peeling apparatus and adherable to a location other than the label main body on the delivery item; and the re-peeling mount sheet region (22,23,24) is configured to have a tapered shape toward an upstream side of a transfer direction of the delivery slip label in the automatic peeling apparatus in which the delivery slip label is to be loaded.