The present disclosure is based on the characteristic that the LED chip emits light when the polarity at each electrode of a LED chip is the same as the polarity of the respective electrode of the power supply to which the electrode of the LED chip is connected. The LED chip sets each with a respective color temperature are connected in opposite manner to two conductive members that are electrically connected to positive and negative electrodes of a power supply. After the power supply is turned on, the LED chip set having the polarity at each electrode the same as the polarity of the respective conductive member to which the electrode connects can emit light, and the LED chip set having the polarity at each electrode opposite to the polarity of the respective conductive member to which the electrode connects can not emit light.