A semiconductor memory apparatus is provided. The semiconductor memory apparatus does not require additional identification information to perform data scrambling and improves the reliability, where the identification information is used to identify whether it is an erased data or a programmed data. A flash memory of the present disclosure includes a scrambling unit 120 scrambling data between an input/output buffer 110 and a page buffer 160. The scrambling unit 120 includes a writing encoder 200 and a reading decoder 220. When an input data is equal to a predetermined bit string, the writing encoder 200 skips the scrambling of the input data. When a read data of the page buffer 160 is equal to the predetermined bit string, the reading decoder 220 skips the descrambling of the read data.