A first method of forming a blood access hole includes: cutting a blood vessel； and connecting the cut blood vessel to a skin. A second method of forming a blood access hole includes: forming an opening in a skin； and connecting a blood vessel, at least a part of which is incised, to the opening. A third method of forming a blood access hole includes: connecting a blood vessel, at least a part of which is incised, to a skin, to open a part of an inner wall of the blood vessel to the atmosphere. A blood access hole 1 in which a blood vessel 10 inside a human body is directly connected to the skin 20 of the human body.
