A retractor (100) has a rigid piercing tube (110) and an expansion body (120). The expansion body (120) has an introduction tube (130) which is received within the piercing tube (110), a movable wire (124) which is received within the introduction tube (130), and stationary wires (126) which are arranged around the movable wire (124). The proximal end of each of the stationary wires (126) is affixed to the distal end of the introduction tube (130). The distal end of each of the stationary wires (126) is joined to the distal end of the movable wire (124). The respective proximal ends of the piercing tube (110), the introduction tube (130), and the movable wire (124) are respectively joined to first, second, and third grip sections (162, 164, 166). The piercing tube (110) is inserted into a luminal organ or a body cavity, the introduction tube (130) is advanced to the distal side, and the movable wire (124) is retracted to the proximal side. As a result, the stationary wires (126) are bent outward and press and displace the inner wall of the luminal organ or an organ within the body cavity. This retractor (100) can be used for an endoscopic surgery.
