The power supply controller performs the power-supply-path protection operation to restrict power supply through the switch element if a value of temperature increase of the power supply path W with respect to the reference temperature To exceeds the temperature threshold value and remove the restriction if the temperature decreases to the temperature threshold value or lower. And the controller performs the switch protection operation to restrict the power supply through the switch element if the value of the flowing current exceeds the current threshold value and remove the restriction after the reference time H elapses. And also the controller adds the additional value F to the value of temperature increase on condition that the value of the flowing current exceeds the current threshold value in the power supply protection operation and compares a post-addition temperature to the temperature threshold value.