A method for decoding a binary image at a high speed, wherein blocks having same pixel values are decoded in clock units, such that a decoding speed increases. The method includes: determining whether a predetermined number of sequential pixels corresponds to any one of a white_run, a black_run, and a combined_run; and if the predetermined number of sequential pixels corresponds to any one of the white_run, the black_run, and the combined_run, decoding the sequential pixels in a block per clock unit.