To fetch data different from back-up data in a backup apparatus in a portable terminal and to get the data inside the portable terminal and the back-up data synchronized with each other.

Only fetch data to be fetched in the portable terminal 1 out of data fed by an external information processor 11 are stored in a fetch data section 63 by an input data sorting part 51. When the portable terminal 1 is connected to a portable terminal connection part 42, a mirroring control unit 52 transfers the fetch data in the fetch data section 63 to a mirroring section 61 or the portable terminal 1 and has the data of the portable terminal synchronized with mirroring data in the mirroring section 61. The method is applicable to a back-up device of the portable terminal, such as a cradle.