PROBLEM TO BE SOLVED: To suppress flickering of a light source when power-up, without deteriorating power factor while lighting the light source.SOLUTION: A DC-DC conversion unit 22 of an LED lighting device 12 outputs a DC power by performing improvement of power factor of DC power and adjustment of voltage by switching operation. A control unit 24 of the LED lighting device 12 compares the voltage of DC power output from the DC-DC conversion unit 22 with a predetermined voltage every first period before an LED 11 is lighted by receiving DC power supply, and every second period longer than the first period after the LED 11 is lighted, and controls the switching operation of the DC-DC conversion unit 22 on the basis of the comparison results.
