POWER SUPPLY PROTECTION CIRCUIT

This power supply protection circuit (10a) controls a protection switch (2) which is inserted into a power supply line that connects a direct-current power supply (1) and a load circuit (3) with eachother; and this power supply protection circuit (10a) is provided with a circuit unit (4a) that is connected to the protection switch (2) and a control unit (5a) that makes a switch between a first state and a second state of the operation state of the circuit unit (4a). The first state is an operation state where the protection switch (2) is able to be driven if the protection switch (2) is a first semiconductor switch, a control terminal of which is connected to a semiconductor layer of a first conductivity type; while the second state is an operation state where the protection switch (2) isable to be driven if the protection switch (2) is a second semiconductor switch, a control terminal of which is connected to a semiconductor layer of a second conductivity type that is different fromthe first conductivity typ