A lighting device which supplies power to an electrode of a discharge lamp to turn on the discharge lamp, includes: a converting circuit which converts inputted direct current into alternating current; a pulse generating circuit which produces a high-voltage pulse from the alternating current received from the converting circuit and applies the high-voltage pulse to the electrode; and a trigger circuit which is disposed between the converting circuit and causes the pulse generating circuit to apply the high-voltage pulse to the electrode, wherein the trigger circuit allows the pulse generating circuit to apply the high-voltage pulse to the electrode in accordance with a drive frequency of the converting circuit.