To improve voltage detection accuracy when the polarity of a voltage applied to a capacitor is inverted.

A voltage monitoring system comprises: a voltage detection circuit 24 detecting a voltage; a capacitor circuit 22 having capacitors C1, C2; an input side switch circuit 21 sequentially applying cell voltages of battery cells V1 to V14 to the capacitors C1, C2; an output side switch circuit 23 applying power storage voltages of the capacitors C1, C2 to detection terminals B1 to B3 of the voltage detection circuit 24; a voltage correction means 25b correcting a voltage detected by the voltage detection circuit 24; and a memory 25a storing charge characteristics in inversion indicating charge characteristics where the polarity of the voltages applied to the capacitors C1, C2 is inverted. The voltage correction means 25 corrects the voltage detected by the voltage detection circuit 24 on the basis of the charge characteristics in inversion stored in the memory 25a when the polarity of the voltage applied to the capacitors C1, C2 by the input side switch circuit 21 is inverted.