A method for suturing a perforation of the present invention comprises the steps of: inserting an observation device into the hollow organ and confirming a proposed incision line for incising the hollow organ; determining a position to be sutured before incising the hollow organ along the proposed incision line; and suturing the perforation by tightening up a suture thread that penetrates through the hollow organ via the position to be sutured after incising the hollow organ along the proposed incision line and performing a medical treatment in an abdominal cavity through the perforation.