A lighting device includes a voltage conversion circuit having at least a switching element connected to a positive potential side of the output terminals of the DC power source unit, and a drive unit which outputs a drive signal to the switching element. The drive unit has a first impedance element with a first impedance which is determined based on a power consumed by the drive unit before a predetermined time has elapsed after a control power source is supplied. A control capacitor for use in generating the drive signal is charged when the switching element is turned off during an on/off operation of the switching element. The lighting device further includes a second impedance element with a second impedance having a resistance component, which is arranged in a path in which the control capacitor can be charged in DC when the switching element does not perform the on/off operation.