POWER SUPPLY EQUIPPED WITH BATTERY UNIT

A fuse element of a SCP is reliably fusion-cut with a simple circuit configuration to interrupt an electric current. In a power supply equipped with a battery unit, a control circuit (7) is configured to control turning on and off of a switch (6) configured to connect the SCP (3) which is connected in series to a battery unit (1) and is configured to interrupt charge and discharge currents in an abnormal state. Battery unit 1 includes battery cells (2) connected in series to one another. The SCP (3) includes fuse element 4 connected in series to an output end of the battery unit (1), and a heater (5) configured to fusion-cut the fuse element (4). The switch (6) includes switching elements (10) each of which has one terminal connected to the heater (5) and another terminal connected to a corresponding one of different-voltage terminals (11) of the battery unit 1. In control circuit (7), a selection circuit (9) is configured to select, according to the voltage detected by the voltage detection circuit (8), a switching element (10) to be turned on, and the switching element (10) which is turned on connects the battery unit (1) to the heater (5) to fusion-cut the fuse element (4).