A memory system includes nonvolatile memory having a plurality of memory cells of storage capacity of a specified number of bits equal to or greater than two bits, and a number-of-rewrites management table managing numbers of rewrites of the memory cells. The memory system includes a controller writing to the memory cells in a number of bits in accordance with a write request of a host, dividing the memory cells into groups in dependence on storage capacity after the numbers of rewrites of the memory cells managed by the number-of-rewrites management table exceed a specified number, and writing to the memory cells of the group corresponding to storage capacity of the number of bits in accordance with the write request of the host.