A secondary battery protection apparatus includes a plurality of secondary battery protection apparatuses. One of two adjacent secondary battery protection apparatuses includes a voltage determination unit that is not affected by a current transfer signal and configured to receive, through a single communication line, the current transfer signal that is transmitted from the other of the two adjacent battery protection apparatuses through the single communication line and an information element based on changes of a voltage value of a voltage transfer signal, and a current determination unit that is not affected by the voltage transfer signal and configured to receive, through the single communication line, the voltage transfer signal that is transmitted from the other of the two adjacent secondary battery protection apparatuses through the single communication line and an information element based on changes of the current value of the current transfer signal.