Connection terminals, corresponding to a plurality of channels, are configured to be connectable to light-emitting units so that driving currents can be supplied to the light-emitting units via the connection terminals individually for each channel. During a non-supply period of the driving currents to the light-emitting units, a sensing process is executed to sense a particular fault. The sensing process includes a first comparison process whereby, with a pull-up current fed toward one of two connection terminals, the voltage at the other connection terminal is compared with a judgment voltage and a second comparison process whereby, with a pull-up current fed toward the other of the two connection terminals, the voltage at the one connection terminal is compared with the judgment voltage.