The invention relates to an undervoltage tripper condition monitoring device which comprises a monitoring circuit, a photoemissive tube and a photoelectric receiving tube, wherein two opposite concave walls are arranged on the inner circle, close to one side of a spring, of a coil, and the photoemissive tube and the photoelectric receiving tube are embedded in the two concave wall positions respectively; the photoemissive tube is connected with a first current-limiting resistor in series and then connected to two ends of the coil in parallel; the monitoring circuit comprises a network voltage detection unit, an output signal of the network voltage detection unit is related with whether the network voltage is undervoltage, and the monitoring circuit outputs a first alarm signal according to the output signal of the network voltage detection unit and the cut-off and connection state of the photoelectric receiving tube and outputs a second alarm signal according to a control output signal of a control panel and the cut-off and connection state of the photoelectric receiving tube. Under the premise that the original functions of the undervoltage tripper are not destroyed, real undervoltage condition and false undervoltage condition can be identified effectively through the simple and cheap additional circuit, and network security operation and undervoltage tripper quality are monitored.