A control circuit is configured to, when switching a state of a light source from an extinguished state to a lighting state, control a voltage conversion circuit so that a second DC voltage has a voltage value which changes according to transmission data containing an activation command. A lighting device is configured to keep the state of the light source at the extinguished state until receiving the activation command from the receiver circuit, and to change the state of the light source to the lighting state when receiving the activation command from the receiver circuit.