There is provided a voltage measuring apparatus for measuring a voltage of an assembled battery in which a plurality of unit cells are connected in series. The voltage measuring apparatus comprises: block voltage detection sections, each section measuring a voltage of each block of a plurality of blocks into which the plurality of unit cells are divided; a reference voltage output section provided in each of the voltage detection sections to output a reference voltage; a difference voltage calculating section which calculates a difference voltage between measured values of the reference voltages measured by two block voltage detection sections; a difference voltage determination section which determines whether each of the difference voltages exceeds a given threshold voltage or not; and an abnormality determination section which determines that abnormality occurs in the voltage measuring apparatus when at least one of the difference voltages is determined as greater than the threshold voltage.