Abstract: In order to add an emergency light function to a fluorescent LED lighting device, thereby increasing safety during a power outage, this LED lighting device, which can be mounted between a pair of sockets for fluorescent lighting, is equipped with a first power supply circuit, which lights the LED using direct current power obtained by converting/rectifying alternating current power supplied from the sockets, and a second power supply circuit, which lights the LED using an embedded battery. An embedded SW controller detects that a sudden drop in the current value or the voltage value in the lighting device, from a prescribed value Von when the lighting switch is turned on to a value that is essentially zero, occurs within a prescribed time T. When the sudden drop occurs two or more times in the prescribed time (FIG. 5), it is determined that a normal operation of turning off the light has been performed, and the light is turned off, and when the sudden drop occurs only once during the prescribed time (FIG.

Abstract: An LED illumination device that can be mounted between a pair of sockets provided to a fluorescent light fixture is provided with a first power source circuit that illuminates an LED using DC power obtained by converting and rectifying AC power supplied from the sockets, and a second power source circuit that illuminates the LED using an internal battery. An IC chip installed in the illumination device detects a first current conduction state in two AC power lines that supply the AC power necessary to drive the first power supply circuit and a second current conduction state in another AC power line, and, on the basis thereof, determines whether the device is in a normal illumination mode, a normal off mode, or an emergency illumination mode. On the basis of the determination results, the LED illumination device is controlled according to the mode.