To provide a battery pack device equipped with an enhanced safety by eliminating risk that the lifetime of the battery is shortened or it is no more serviceable whichever external charger is used for performing charging.

This battery pack device is structured so that the charging current at charging a battery cell 101 is sensed by a current detection resistance 103, that a control signal having a potential in accordance with the detection result of the resistance 103 is prepared by a controlling means (105, etc.), and that the path in which the charging current flows is opened and closed on the basis of the potential of the control signal using a current limiting FET(field effect transistor) 107. That is, when the resistance 103 has sensed a charging current over a certain level, the controlling means (105, etc.), opens the FET 107 and stops charging.