A method for suturing a perforation comprises the steps of: observing an area around the perforation from an inside of a hollow organ by an observation device inserted from a natural opening of a living body observing the area around the perforation from a body cavity side of the hollow organ by an observation device inserted from the natural opening of the living body thrusting a needle of a suture unit inserted from the natural opening of the living body into a tissue around the perforation of the hollow organ to make a suture thread puncture the tissue via the needle and closing the perforation by tightening up the suture thread puncturing the tissue.
