The utility model discloses a fault monitoring apparatus of an electrified display device. The fault monitoring apparatus is composed of an electrified display device, a voltage input module, a voltage sampling module, a fixed value comparison module, and a logic output module. The electrified display device, the voltage input module, the voltage sampling module, the fixed value comparison module, and the logic output module are successively connected. The logic output module consists of an or gate logic unit, a communication network interface, and a buzzer. The electrified display device and the voltage input module are connected by a mutual inductor. The voltage sampling link is formed by an isolation transformer, a proportion operation circuit, and a voltage following circuit; and the fixed value comparison link is formed by two comparators. According to the technical scheme, the voltage of the electrified display device of the distribution system is used as the pointcut and the characteristic of the circuit electrification state is reflected reliably by using the height of the electrified display device; and sampling and monitoring are carried out on the state of the electrified display device in real time, thereby achieving an objective of circuit voltage monitoring.