A method of resecting entire layers of a digestive tract includes: an insertion step of inserting an endoscope into the digestive tract； an everting step performed after the insertion step, to suture mucosal layers located on both sides of a target region including a lesion, cover the target region with the mucosal layers, and evert a tract wall including the target region to a side of an abdominal cavity, in the digestive tract； and an incision step performed after the everting step, to position an incision tool between the target region and the mucosal layers to incise the tract wall around the lesion by the incision tool.
