Abstract: A cellular phone charger having not only a charging function of charging a cellular phone but also a data backup function of backing up various data stored in the cellular phone and writing backup data to the cellular phone. The charger is equipped with a telephone memory control unit having a memory for storing various data stored in a cellular phone, a charging control unit for controlling charging of the cellular phone, and a voltage conversion unit for converting an input voltage that is supplied from a home power line or the like into drive voltages for the telephone memory control unit and the charging control unit.