A submarine repeater system, having a power supply path-switching device, the power supply path-switching device comprising: power consumption means that operates by supplied power; grounding means; first switching means for connecting a first power supply line (61, 612), the power consumption means, and the grounding means to each other, based on a first control signal; and second switching means for connecting a second power supply line (62, 622), the power consumption means, and the grounding means to each other, based on a second control signal, wherein during a normal operation of the first power supply line (61, 612) and the second power supply line (62, 622), the power consumption means generates the first control signal and the second control signal for connecting the first power supply line and the second power supply line, respectively, to the power consumption means, when a failure has occurred in the first power supply line (61, 612), the power consumption means grounds the first power supply line (61, 612), generates the first control signal for connecting one end of the power consumption means to the grounding means, and generates the second control signal for connecting the second power supply line (62, 622) to another end of the power consumption means, and characterised by when a failure has occurred in the second power supply line (62, 622), the power consumption means generates the first control signal for connecting the first power supply line (61, 612) to one end of the power consumption means, grounds the second power supply line (62, 622), and generates the second control signal for connecting another end of the power consumption means to the grounding means. power consumption means that operates by supplied power; grounding means; first switching means for connecting a first power supply line (61, 612), the power consumption means, and the grounding means to each other, based on a first control signal; and second switching means for connecting a second power supply line (62, 622), the power consumption means, and the grounding means to each other, based on a second control signal, wherein during a normal operation of the first power supply line (61, 612) and the second power supply line (62, 622), the power consumption means generates the first control signal and the second control signal for connecting the first power supply line and the second power supply line, respectively, to the power consumption means, when a failure has occurred in the first power supply line (61, 612), the power consumption means grounds the first power supply line (61, 612), generates the first control signal for connecting one end of the power consumption means to the grounding means, and generates the second control signal for connecting the second power supply line (62, 622) to another end of the power consumption means, and characterised by when a failure has occurred in the second power supply line (62, 622), the power consumption means generates the first control signal for connecting the first power supply line (61, 612) to one end of the power consumption means, grounds the second power supply line (62, 622), and generates the second control signal for connecting another end of the power consumption means to the grounding means.