Provided are a battery protection IC adaptable to any number of batteries connected in series without increasing a breakdown voltage thereof, and a battery device including the battery protection IC mounted thereon. A charge control signal input terminal and a discharge control signal input terminal of one battery protection IC are provided with a clamp circuit (121), and hence an output driver (112) of another battery protection IC connected to those terminals is not applied with a voltage equal to or higher than a breakdown voltage. Accordingly, the breakdown voltage of the battery protection IC is not required to be high.