A personal digital assistant comprises a loss detector to detect a lost state and a value information retainer for retaining a value assessment index, which are numerical values indicating data values. When a lost state is detected by the loss detector, a data recovery sequence is determined based on the data values and data is transmitted to another terminal. In determining the recovery sequence, electrical energy required for data transmission is calculated using a power consumption table and the remaining battery power level measured by a remaining battery power level meter is referenced.