A memory device includes a nonvolatile memory and a controller. The nonvolatile memory includes a storage area having a plurality of memory blocks each including a plurality of nonvolatile memory cells, and a buffer including a plurality of nonvolatile memory cells and configured to temporarily store data, and in which data is erased for each block. If a size of write data related to one write command is not more than a predetermined size, the controller writes the write data to the buffer.