A battery voltage monitoring apparatus to monitor a voltage of an assembled battery having a plurality of battery cells, the battery voltage monitoring apparatus comprises a first voltage sensor module having a voltage sensor and a first and a second module terminals connected to the voltage sensor, a second voltage sensor module having a voltage sensor different from the voltage sensor included in the first voltage sensor module and a third module terminal connected to the voltage sensor, a first terminal connected to the first and the third module terminals, a second terminal connected to the second module terminal, and a voltage clamp circuit to clamp a voltage between the first and the second terminals disposed between the first and the second terminals.