Endoscopic surgical operation method includes: a step of lifting a living tissue including an diseased tissue located distally relative to an operation channel of an endoscope inserted through a natural orifice a step of suturing a proximal region and a distal region of the living tissue positioned basal relative to the diseased tissue lifted by a suturing means section projecting distally from the operation channel of the endoscope after the lifting and a step of resecting the living tissue between the sutured regions and the diseased tissue endoscopically after suturing the proximal region and the distal region of the living tissue surrounding the diseased tissue.
