Provided is a technology capable of protecting a charge/discharge control circuit and a battery device from a reverse connection state without a separately provided protection circuit. The charge/discharge control circuit to be contained in a battery device including a secondary cell, an external positive terminal and an external negative terminal, and FETs which control charging and discharging of the secondary cell, respectively, includes: VDD and VSS terminals; a charge control terminal; a discharge control terminal; a voltage detection terminal to which a voltage applied to the external positive terminal is supplied; an NMOS transistor communicates the discharge control terminal and the voltage detection terminal; and a bipolar transistor having a collector to be connected to a drain of the NMOS transistor, an emitter to be connected to a source of the NMOS transistor, and a base to be connected to a bulk of the NMOS transistor and the VSS terminal.