A medical device including: an insertion portion configured to be inserted into a body； and a sheet provided at a distal end of the insertion portion, the sheet being configured to cover a body wall. The sheet including: an attaching portion provided around a periphery of the sheet, the attaching portion being configured to directly contact with the body wall； and a notifying portion for notifying a surgeon that an incision has been made through the body wall and towards a surface of the sheet.
