A circuit for measuring voltage of a battery and a power storage system using the same. According to one aspect, the circuit includes a switching element connected to the battery and configured to output a first signal at a first voltage level. The switching element is configured to be turned-on in response to a voltage measuring control signal. The circuit also includes a voltage conversion circuit connected to the switching element. The voltage conversion circuit is configured to output a second signal at a second voltage level that is proportional to the first voltage level. An analog-digital converter is configured to receive the second signal and convert the received second signal into a digital signal. A controller is configured to transfer the voltage measurement control signal to the switching element, and receive the digital signal from the analog-digital converter.