PURPOSE: To provide a charger, an emergency power supply, and an emergency lighting fixture employing the emergency power supply, in which transistors in a constant voltage circuit are protected positively against breakdown due to discharge of a smoothing capacitor when output voltage from the constant voltage circuit drops due to interruption of AC power supply.

CONSTITUTION: The emergency power supply comprises an AC power supply 1, a rectifier 5 for rectifying AC power supply voltage, a series dropper circuit 6 comprising a transistor 61 and arranged on the output side of the rectifier 5, and a smoothing capacitor 7 connected across the series dropper circuit 6 on the output side thereof, wherein a capacitor 20 is connected between the main electrode and the base of the transistor 61 in the series dropper circuit 6 on the output side thereof. Consequently, charges from the smoothing capacitor 7 bypass the base and the main electrode of the transistor on the output side thereof thus protecting the transistor in the series dropper circuit 6 against breakdown.