The invention relates to an electrosurgical instrument (5) for an endoscope or a catheter, which can be operated by means of a high-frequency current, contact electrosurgical treatment and non-contact plasma coagulation in an ionisable gas. A stationary electrode (33) is arranged on the distal end of a guiding tube (7) that can be introduced into the instrument channel (1) of an endoscope catheter (3), and when the electrosurgical electrode for the contact treatment is in the retracted position in the guiding tube (7), the stationary electrode is connected to the electrosurgical electrode (11) by means of a contact element (37).The retracted position of the electrode (11) can, but not necessarily, be maintained by an abutment (21) of a handling device (13) and/or by a suitable arrangement and measurement of the contact element (37). The retracted position of the electrode (11) does not need to be optically controlled.