A method to divide a file or merge files using a file allocation table (FAT) in which the method to divide a file includes storing data of a first cluster, among data intended to be separated from the file, into a second cluster, and generating a first cluster chain and a second cluster chain using a file allocation table (FAT), the first cluster chain containing data remaining in the first cluster, and the second cluster containing data existing in the second cluster. As a result, time delay due to a file copy process and shortening of a lifespan of NAND flash are prevented, and a reserve capacity for editing purposes is minimized.