A memory device can be connected to a host through an interface. The memory device includes a nonvolatile memory which includes a plurality of blocks, and a controller which is electrically connected to the nonvolatile memory. In a case where a read command is received from the host, the controller reads first data designated by the read command from a first block of the nonvolatile memory, to transmit the first data to the host, and to write the first data to a second block of the nonvolatile memory instead of the first block.