An LED lighting device 1 lights LED blocks 4a and 4b which correspond to a plurality of functions of an illuminator such as headlights and are connected in series. The LED blocks 4a and 4b are connected in series with a current converting unit 5. While the LED blocks 4a and 4b are supplied with a current Ia from a single DC/DC converter unit 3, the LED block 4b is supplied with a current Ib that passes through conversion by the current converting unit 5 and that differs from the current Ia the DC/DC converter unit 3 outputs. Thus, the LED blocks 4a and 4b are each lit with appropriate brightness.