POWER SUPPLY SYSTEM

A power supply system includes: a first in-vehicle unit and a second in-vehicle unit; a first supply line normally supplying electric power from the first power supply unit to the first in-vehicle unit; a second supply line normally supplying electric power from the second power supply unit to the second in-vehicle unit; a crossover line relaying electric from the first supply line to the second supply line to be able to supply electric power under abnormal conditions; a power supply rectifier provided on a second power supply unit side of the relay supply line on the second supply line and configured to pass power to the second in-vehicle unit; a crossover rectifier provided on the crossover line and configured to pass power from the first supply line side to the second supply line; and a relay unit.