The invention relates to a bipolar electrosurgical instrument for ablating biological tissue, including an elongated shaft and two ablation electrodes, which are arranged one behind the other on the shaft in the longitudinal direction of the shaft and form a surface portion of the shaft, the ablation electrodes being electrically conductive and electrically separated from each other by an insulator, wherein the instrument has at least one measurement electrode, which is electrically insulated from the ablation electrodes and arranged between the two ablation electrodes in the immediate vicinity of one of the two ablation electrodes.
