The present invention provides a memory device that can flexibly decide the data to be preread. The memory device according to the present invention includes: a nonvolatile memory; a buffer memory having a higher access speed than the nonvolatile memory; and a control circuit. The control circuit creates a preread data management table that associates a logical address of preread data specified by a preread command inputted from the outside and a buffer memory address for storing the preread data. Moreover, the control circuit reads data specified by the command from the nonvolatile memory and stores it in the buffer memory as preread data. When a logical address specified in a read command inputted from the outside matches a logical address associated by the preread data management table, the control circuit outputs corresponding preread data from the buffer memory.