The voltage detection circuit 3 is provided with an isolation transformer 4 having its primary side connected to battery 2 connection nodes 10, a switching device 5 connected to the primary side of the isolation transformer 4, an isolated input circuit 7 that switches the switching device 5 ON and OFF, and a secondary voltage detection section 8 that detects output voltage from the secondary side of the isolation transformer 4. In the voltage detection circuit 3, the series input circuit 6 of the isolation transformer 4 primary side and the switching device 5 are connected to battery 2 measurement nodes, the switching device 5 is switched ON and OFF with a given periodicity by the isolated input circuit 7, and the output voltage from the secondary side of the isolation transformer 4 is detected by the secondary voltage detection section 8 to determine the voltage across the measurement nodes.