A data writing method is disclosed. In a memory system comprising a NAND flash memory and a controller which controls the memory, the memory system storing data provided from a host to the NAND flash memory, the data writing method comprises a steps of specifying a column address in which a column failure which has occurred in the NAND flash memory by the controller, and a step of, during writing into the NAND flash memory, writing data of a first logic level into a memory cell which corresponds to the specified column address regardless of write data provided from the controller.