To enable to disturb turning on a light emitting body when luminosity in the ambient environment is brighter than prescribed luminosity, by generating fading effect for a prescribed period after switching from ON to OFF.

When a switch 98 is turned OFF in the dark night, an LED(light emitting diode) 90 is turned ON at prescribed luminosity. It is caused by that power for the LED 90 is supplied by a capacitor 70 completely charged up to the voltage of a constant voltage power source 33. However, when the switch 98 is opened, power for the LED 98 is supplied from discharge of the capacitor 70. Though the capacitor 70 is charged when the switch 98 is closed, a power source 33 is cut with the connection when the switch 98 is opened and the capacitor 70 discharges to supply power to the LED 90. As the result of voltage lowering during discharging, brightness of the LED 90 is lowered. It generates fading effect for a period until the switch 98 is closed again.