MANAGEMENT DEVICE AND POWER SUPPLY SYSTEM

In management device (20), voltage measurement circuit (30) measures a voltage of each of a plurality of cells (E1 to E12) connected in series. A plurality of voltage measurement lines (L1, L2, L3,...) connect between respective nodes of the plurality of cells (E1 to E12) and respective voltage measurement terminals of voltage measurement circuit (30). A lower reference potential line (ground potential line Lg) connects between a lower node of lowermost cell (E1) of the plurality of cells (E1 to E12) and a lower reference terminal of voltage measurement circuit (30). Voltage dividing resistor (Rv1 or Rv2) is connected between a predetermined fixed potential and lowermost voltage measurement line (L1). Controlling circuit (40) monitors the voltage between a voltage dividing point potential of voltage dividing resistor (Rv1 or Rv2) and a lower reference potential of voltage measurement circuit (30), and diagnoses presence or absence of disconnection of lowermost voltage measurement line (L1) or the lower reference potential line (ground potential line Lg).