An image predictive decoding method for an image predictive decoding device, the method comprising: a first step for extracting, from compressed data where an image is divided into a plurality of regions and encoded, encoded data of identifying information that specifies a region to be used in producing a prediction signal of a target region, and encoded data of a residual signal; a second step for specifying a neighbouring region from a plurality of neighbouring region candidates neighbouring the target region based on identification information decoded from the encoded data of the identification information, and producing a prediction signal of the target region from a reconstructed signal by using mode information specifying inter-picture prediction, a reference picture number, and a motion vector, all of which are prediction information associated with the neighbouring region specified and applied to a first of two partitions of the target region, the first partition having a specified width; a third step for restoring a reproduction residual signal of the target region from the encoded data of the residual signal; a fourth step for producing a reproduction signal of the target region based on the prediction signal of the target region and the reproduction residual signal; and a fifth step for storing the reproduction signal of the target region as the reconstructed signal, wherein the second step includes determining availability of prediction information associated with a neighbouring region on the left of the target region and availability of prediction information associated with a neighbouring region above the target region based on a predetermined rule, and either adopting the neighbouring region on the left and the neighbouring region above as the plurality of neighbouring region candidates if the prediction information associated with each of the neighbouring region on the left and the neighbouring region above are determined as having availability for producing the prediction signal of the target region, or determining the prediction information associated with the neighbouring region on the left or the neighboring region above as being unavailable among from the plurality of neighbouring region candidates if the respective prediction information is identical to the prediction information associated with the target region. a first step for extracting, from compressed data where an image is divided into a plurality of regions and encoded, encoded data of identifying information that specifies a region to be used in producing a prediction signal of a target region, and encoded data of a residual signal; a second step for specifying a neighbouring region from a plurality of neighbouring region candidates neighbouring the target region based on identification information decoded from the encoded data of the identification information, and producing a prediction signal of the target region from a reconstructed signal by using mode information specifying inter-picture prediction, a reference picture number, and a motion vector, all of which are prediction information associated with the neighbouring region specified and applied to a first of two partitions of the target region, the first partition having a specified width; a third step for restoring a reproduction residual signal of the target region from the encoded data of the residual signal; a fourth step for producing a reproduction signal of the target region based on the prediction signal of the target region and the reproduction residual signal; and a fifth step for storing the reproduction signal of the target region as the reconstructed signal, wherein the second step includes determining availability of prediction information associated with a neighbouring region on the left of the target region and availability of prediction information associated with a neighbouring region above the target region based on a predetermined rule, and either adopting the neighbouring region on the left and the neighbouring region above as the plurality of neighbouring region candidates if the prediction information associated with each of the neighbouring region on the left and the neighbouring region above are determined as having availability for producing the prediction signal of the target region, or determining the prediction information associated with the neighbouring region on the left or the neighboring region above as being unavailable among from the plurality of neighbouring region candidates if the respective prediction information is identical to the prediction information associated with the target region.