The invention relates to a heater operation monitoring device and belongs to the power system substation power equipment heating device field. The heater operation monitoring device is structured in the following manners that: a heater (1) is connected with a monitor (3) through a current transformer (2); the monitor (3) is provided with an indicating lamp D2 (4); and the indicating lamp D2 (4) is a light-emitting diode. According to the heater operation monitoring device, whether the heater is abnormal or not can be accurately judged through lamp light indication. The heater operation monitoring device of the invention is required to effectively solve practical problems in field work. The heater operation monitoring device can be sized to fit the practical spatial sizes of components such as a switch cabinet and a circuit breaker mechanism box; and the operating condition of the heater can be indicated through lamp light. The heater operation monitoring device has the advantages of small size, portable convenience, simple and reliable installation, and convenient check, and is suitable for installation of heaters in different models, and can assist in effectively improving the efficiency of the check and maintenance of a substation.