1. A nonvolatile memory comprising: a plurality of memory banks; and a control circuit, wherein each of said memory banks comprises a nonvolatile memory unit and two buffer memories, wherein said nonvolatile memory unit is capable of storing data, wherein said two buffer memories are capable of storing a first length data which length is storable data length to said nonvolatile memory unit at once, and wherein said control circuit controls, in response to instructing an access operation, a first transferring between said nonvolatile memory unit and a first buffer memory of said buffer memories and, in parallel to said first transferring, controls a second transferring between a second buffer memory of said buffer memories and outside of nonvolatile memory.