Provided is a digestive-tract treatment method including: pulling, inside a digestive tract (A), an end portion of a first wall portion (A1) positioned at a rim of a treatment target site (B), and moving the first wall portion (A1) to a position on a second wall portion (A2) on an opposite side of the treatment target site (B) from the first wall portion (A1)； and joining the first wall portion (A1) and the second wall portion (A2) in a state in which the first wall portion (A1) and the second wall portion (A2) are layered.
