A deletion instruction of data stored in a nonvolatile memory is input, a determination is made whether the nonvolatile memory has reached an end of its rewrite operating life in accordance with the input deletion instruction, an instruction for setting a password to the nonvolatile memory is accepted when it is determined that the nonvolatile memory has reached the end of its rewrite operating life, and the password is set to the nonvolatile memory in accordance with the accepted instruction.