An assembled battery voltage detecting apparatus includes a sampling switch section which samples a voltage of each of single batteries, capacitors charged with voltages of single batteries, a transfer switch section to transfer a charge voltage charged in each of the capacitors, a ground potential setting switch section which, in the case of reading the voltage charged in the capacitor, connects a reference electric potential of the capacitor to a grounding terminal of a voltage detecting apparatus, and a voltage detecting circuit which controls a switching timing of each of the above switches, and then reads a voltage of each capacitor.