CONTROL DEVICE

A control device for an in-vehicle power supply system, comprising: a main power supply that supplies electric power to a load mounted on a vehicle; a redundant power supply that includes a capacitor for storing electric power and supplies electric power from the capacitor to the load when the main power supply fails; and a relay that switches the power supply source to the load to either the main power supply or the redundant power supply, wherein after the ignition of the vehicle is turned off, the discharge process of the capacitor is started, and the fixation prevention process of the relay using the electric power of the capacitor is executed during the discharging process of the capacitor.