An image intra prediction method and image intra prediction apparatus and a decoding apparatus and a decoding method using the image intra prediction method are provided. The image intra prediction method includes: backing up boundary pixel values adjacent to a block that is to be decoded; correcting the boundary pixel values adjacent to the block that is to be decoded based on correlations between the boundary pixels and pixels adjacent to the boundary pixels; predicting a block that is to be decoded according to an intra mode, from among a plurality of intra modes, based on the corrected boundary pixel values; and restoring the boundary pixel values from the backed-up values.