A non-volatile memory device comprises a memory cell array comprising memory cells arranged in rows connected to corresponding word lines and columns connected to corresponding bit lines, a page buffer that stores a program data, a read-write circuit that programs and re-programs the program data into selected memory cells of the memory cell array and reads stored data from the programmed memory cells, and a control circuit that controls the page buffer and the read-write circuit to program the selected memory cells by loaded the program data from in page buffer and to re-program the selected memory cells by re-loaded the program data in the page buffer.