POWER SUPPLY MANAGEMENT DEVICE

There is provided a power supply control device 10 which can determine a deterioration state of a sub-battery 30 appropriately and determine permission/prohibition of running of a vehicle based on the result of deterioration determination. The power supply control device 10 has a first power supply 16, a second power supply 30 composed of a secondary battery, a DC/DC converter 14 which converts a voltage of the first power supply 16 and enables the second power supply 30 to be charged with the converted output voltage, and a controller 31 which controls the DC/DC converter 14 and determines deterioration of the second power supply 30. The controller 31 controls the DC/DC converter 14 during a charge period so that the output voltage value of the DC/DC converter 14 is greater than or equal to a predetermined voltage value, to thereby charge the second power supply 30, controls the DC/DC converter during a predetermined discharge period after the charge period so that the output voltage value of the DC/DC converter 14 is less than the predetermined voltage value, to thereby discharge the second power supply 30, and determines deterioration of the second power supply 30 according to a state of charge of the second power supply 30 after the discharge period.