A data management method for memory and a memory apparatus are provided. The memory includes a number of memory pages. Each of the memory pages includes multiple memory cells. Each of the memory cells includes a first bit and a second bit. Each of the memory cells has a first logical state, a second logical state, a third logical state, and a fourth logical state. The data management method for memory includes the following steps. A data update command corresponding to a logical address is received. The logical address corresponds to a physical address before receiving the data update command. A sanitizing voltage is applied to a first target memory cell of the memory cells in a target memory page of the memory pages located at the physical address. The logical state of the first target memory cell is changed.