The voltage measuring apparatus is connected to a plurality of battery cells connected to each other in series to measure respective voltages of the battery cells. The voltage measuring apparatus includes a sample/hold amplifier configured to sample and hold positive electrode and negative electrode voltages of the battery cells to generate first and second output voltages, a differential voltage converter configured to generate a battery cell voltage according to a voltage difference between a positive input terminal and a negative input terminal, and a switching unit configured to control the first and second output voltages and connection between the positive input terminal and the negative input terminal so that a polarity of the voltage difference is constant. The sample/hold amplifier electrically insulates the switching unit from the battery cells.