In order to provide a power supply path-switching device, a power supply path-switching system, and a power supply path-switching method with which it is possible to utilize to the maximum equipment in which a failure has not occurred without imparting a power supply function to a branch station side even when a failure has occurred in the power supply function of the trunk station side, a power supply path-switching device (10) is provided with a first switching means (20), a second switching means (30), a grounding means (40), and a power consumption circuit (50) that operates by being supplied with the power supply. When a failure occurs in a first power supply line (61), the power consumption circuit (50) grounds the first power supply line (61), one end of the power consumption circuit (50) being connected to the grounding means (40) and a second power supply line (62) being connected to the other end of the power consumption circuit (50). When a failure occurs in the second power supply line (62), the power consumption circuit (50) grounds the second power supply line (62), the first power supply line (61) being connected to one end of the power consumption circuit (50) and the other end of the power consumption circuit (50) being connected to a grounding means (24).