Device for treating gastroesophageal reflux disease and method for treating gastroesophageal reflux disease

A method for treating gastroesophageal reflux disease, the method comprising:

• inserting an insertion portion of an endoscope from a cardia into a stomach, the insertion portion including a distal end portion that is bendable, and an observation mechanism having an image sensor;
• bending the distal end portion to form a bend therein and position a cautery unit and a cardiac region in a field of view of the observation mechanism, the cautery unit being configured to cauterize living tissue;
• operating the insertion portion or the cautery unit to bring the cautery unit into contact with a first region of a stomach wall around the cardia in a separation state in which the cautery unit and a proximal portion of the insertion portion that is proximal of the bend in the distal end portion are separated from each other by a predetermined distance or more;
• cauterizing the first region while leaving a mucosal layer of the first region;
• operating the insertion portion while maintaining the separation state to change a position of the cautery unit with respect to the stomach wall;
• and
• operating the insertion portion or the cautery unit while maintaining the separation state to bring the cautery unit into contact with a second region of the stomach wall that is different from the first region and cauterizing the second region while leaving a mucosal layer of the second region.