Abstract: An electrosurgical instrument comprises a cutting working portion (1) which incorporates two ring-shaped electrodes (3, 4) separated with a disk (2) from an insulating material, a power actuator to impart rotation to the working portion (1), and current leads, each adapted to interact with the respective ring electrode (3 or 4). The cutting working portion (1) is additionally provided with a knife (14) whose cutting edge (15) is shaped as a circular arc whose size is not in excess of 90 arc degrees of the outer circumference of the working portion (1). The cutting edge (15) may stand over the outer circumference of the disk (2), or be an integral part thereof.