In a power supply controller 10 having a self-protective mechanism for performing, intermittently or periodically, a forced ON-OFF operation which causes a power MOSFET 15 to perform an automatically restorable primary disconnecting operation and a restoring operation when an overcurrent anomaly or an short-circuiting anomaly is detected, an automatically unrestorable secondary disconnecting operation is performed when the accumulated amount of the duration of the forced ON-OFF operation reaches an accumulation threshold.