The present invention provides an image encoding method and an image decoding method. The image decoding method of the present invention may comprise: obtaining intra-frame prediction information of a current block from a bitstream; inducing an intra-frame prediction mode of the current block on the basis of the intra-frame prediction information; determining a reference region for intra-frame prediction of the current block; and performing intra-frame prediction of the current block on the basis of the intra-frame prediction mode and the reference region.