An instrument for large-area ablation of the mucosa including at least one first gas supply line and at least one second gas supply line whose distal ends are arranged to form an acute angle (α), so that the ends diverge distally. A free space between the distal ends of the gas supply lines allows the user to view the tissue region behind the distal end of the instrument. Due to the acute angle (α), electrodes arranged at least partially in the ends of the gas supply lines generate a wide plasma beam with which the mucosa ablation can be performed. The instrument can be guided precisely due to the view through the free space. A connecting element according to the invention is provided for attaching the ends of the gas supply lines.
