To provide a power source system in which temperature rise of a voltage converter is effectively suppressed when an abnormality occurs in the cooling system of an inverter.

The power source control system 10 is constituted by comprising a power source circuit 12 including a battery device 14, the voltage converter 20, an inverter unit 34, an inverter cooling system 40, and a low voltage-actuating auxiliary machine 50; and a control part 60. The control part 60 is constituted by comprising an inverter cooling system status-acquiring module 62 for acquiring the status of the inverter cooling system 40 and determining whether the status is normal or abnormal, a battery device WIN, WOUT-limiting module 64 for limiting WIN and WOUT of the battery device 14 when the inverter cooling system is abnormal, and an auxiliary machine output-limiting module 66 for limiting the output of the low voltage-actuating auxiliary machine 50 when the inverter cooling system 40 is abnormal.