In order to plan preventive measures from the occurrence of electric power transmission line accident, a power transmission line anomaly approaching alarm system was developed to automatically alarm the operators and surveillants. The surveillance system, composed of camera, surveillance unit proper and alarm receiving portion, generates alarm and indicate hazard to the operators, when animal invades a hazardous area designated on the monitor. Wireless telegraph for the alarm transmission use used frequency around a 322MHz band with the Radio Ray law and preventive measures from noise, taken into consideration. The prototype is characterized by unnecessary ancillary fitting to the surveillance object, rare erroneous operations and high reliability. While the hazardous area can be simply designated, changed and released, as made by volume on the control panel. It is moreover easy to designate, as done by confirming the surveillance object on the display. It is also possible in multidimensional surveillance and easy to use on site. 7 figs.