A power supply circuit for supplying power to an electric load of a vehicle includes a relay and a relay control circuit. The relay is configure to be turned on when enabling the supply of power to the electric load and configured to be turned off when interrupting the supply of power to the electric load. The relay control circuit is configured to turn on the relay when an ignition of the vehicle is on regardless of a state of an operation part that is to be operated by a driver to operate the electric load.