A light source driving circuit includes a power supply circuit, a first dimming circuit, and a control circuit. The power supply circuit has a control terminal and an output terminal that is connected to a terminal of a first light-emitting element. The first dimming circuit has a first terminal connected to the other terminal of the first light-emitting element, a second terminal connected to a common potential, and a pulse width signal input terminal. The control circuit is connected between the pulse width input terminal of the first dimming circuit and the control terminal of the power supply circuit. The first dimming circuit determines an ON/OFF state according to a logic state of the pulse width signal. The power supply circuit determines whether or not to output the voltage. The control circuit delays the power supply circuit, turns off the power supply circuit, and delays the first dimming circuit.