Abstract: A device for bipolar high-frequency coagulation of biological tissue between two contact faces of a coagulating instrument. The two contact faces are connected to an output of a high-frequency generator. A temperature sensor is arranged near each of the two contact faces. A circuit for evaluating the measured temperatures and/or the temperature differential controls the coagulation temperature and the shutoff of the high-frequency generator as a preselected temperature or temperature differential is exceeded. Moreover, an indicating device is provided for acoustically and/or optically indicating the temperatures on the contact faces as well as the temperature differential between the contact faces.