An LED lighting system capable of performing a dimming function for adjusting brightness of output light to decrease includes: an LED light source comprising three or more LED channels that are respectively configured to emit light of different color temperatures; and an electric circuit configured to electrically drive the three or more LED channels. The electric circuit is configured to drive the three or more LED channels so that brightness and color temperature of the output light obtained by the LED light source decrease together in conjunction with each other during dimming in which the brightness of the output light decreases.