PURPOSE: To automatically vary the quantity of light in a simple structure by arranging a voltage for applying to a lamp in serial with an impedance circuit, and by arranging a relay and a timer in parallel with each other so as to obtain variation in time, for a lighting apparatus provided with a lamp and a ballast.

CONSTITUTION: After the time setting for a timer 3 and for timer 4 is carried out, when a push button switch 1 is pushed, an a-contact 2-1 of a relay 2 is closed, and current is run in a circuit 9, and the timer 3 is thus excited. When the set time set for the timer 3 has passed, an a-contact 3-1 is closed, and the voltage correspondent to a resistance 5 is applied to a lighting apparatus 7 of a circuit 10, and the apparatus is thus lighted. When the time set for the timer 4 has passed, a b-contact 4-1 is opened, and no current is run in the circuit 10, while an a-contact 4-2 of the timer 4 is closed, and the voltage correspondent to a resistance 6 is applied to the lighting apparatus 7 from a circuit 11. When the resistance 5 is made larger than the resistance 6, the voltage applied to the lighting apparatus 7 is shifted from a small level to a large level, while the brightness is shifted from a small level to a large level, and the quantity of light can be varied in this way according to a timer setting.