POWER SUPPLY SYSTEM

A power supply system for a vehicle for controlling power supply from a second power supply provided for backup of the first power supply to a plurality of in-vehicle equipment, comprising a relay inserted between the second power supply and the first in-vehicle equipment, when a collision of the vehicle is detected during the backup operation of the first power supply by the second power supply, the electric power supplied from the second power supply to the second in-vehicle equipment, characterized in that it supplies in parallel to the first in-vehicle equipment via the relay.