Provided is a tissue excision method that excises a partial tissue within an excision region set in a hollow organ over an entire thickness direction. The tissue excision method includes a first process of gripping a peripheral edge portion of the excision region from the inside of the hollow organ a second process of moving the portion and drawing the folded hollow organ into a slit with a predetermined width a third process of suturing a part located outside the excision region so as to be integral over the thickness direction and a fourth process of cutting the portion of the drawn hollow organ along the peripheral edge of the excision region. In the second process, a portion of a fluid within the hollow organ is moved out of the hollow organ to keep the internal pressure within a fixed range while drawing the portion of the hollow organ.
