1. An image predictive decoder comprising a memory that stores a program executable by the image predictive decoder to: extract, from compressed data in which an image is divided into a plurality of regions and encoded, encoded data of identification information that specifies an identification of a region that is not agreed upon to use in advance between an image predictive encoder and the image predictive decoder and is used to produce a prediction signal of a target region, and encoded data of a residual signal; read out the identification specified in the identification information; prepare a list that consists of entries corresponding, respectively, to a plurality of neighbouring regions that neighbour the target region; select a neighbouring region from the list, the selected neighbouring region being identified by the identification specified in the identification information; produce the prediction signal of the target region by using prediction information for the specified neighbouring region comprising (i) mode information that specifies an inter-picture prediction method, (ii) a reference picture number, and (iii) a motion vector, all of which are used for prediction of the specified neighbouring region; restore a reproduction residual signal of the target region from the encoded data of the residual signal; produce a reproduction signal of the target region based on the prediction signal of the target region and the reproduction residual signal; and store the reproduction signal of the target region as the reconstructed signal in the memory.