An artificial blood vessel configured to be connected to blood vessels of a patient, comprising: a trunk portion which is configured to act as a bridge between the patient's blood vessels; and a branch portion branched from the trunk portion and in which an access port , into which a needle for extracting a fluid from a body of the patient or introducing the fluid into the patient's body can be inserted, is placed, wherein the trunk portion comprises a tubular reinforcement member having a generally cylindrical shape and a mesh-like structure and being integrated with a blood vessel wall of the artificial blood vessel , placed at a position where the branch portion branches and an adjacent portion thereto, and having a rigidity to prevent closure of the artificial blood vessel when a lateral force is applied, wherein the blood vessel wall of a portion where the reinforcement member is placed has two layers including an inner wall and an outer wall , the reinforcement member is sandwiched between the inner wall and the outer wall , and the reinforcement member is not exposed to the outside, wherein the reinforcement member has an opening defined by an annular-shaped annular portion and wherein the opening corresponds to the branch portion and is disposed on the side surface at substantially the center in the length direction of the reinforcement member , characterized in that at the location of the annular potion , the inner wall and the outer wall are wrapped toward the outer surface and the inner surface, respectively, and wherein the branch portion has a branch portion blood vessel wall and wherein an end of the branch portion blood vessel wall is folded such that it forms a folded portion, wherein the folded portion is connected to the inner wall or outer wall of the blood vessel wall of the trunk portion around the annular portion . a trunk portion which is configured to act as a bridge between the patient's blood vessels; and a branch portion branched from the trunk portion and in which an access port , into which a needle for extracting a fluid from a body of the patient or introducing the fluid into the patient's body can be inserted, is placed, wherein the trunk portion comprises a tubular reinforcement member having a generally cylindrical shape and a mesh-like structure and being integrated with a blood vessel wall of the artificial blood vessel , placed at a position where the branch portion branches and an adjacent portion thereto, and having a rigidity to prevent closure of the artificial blood vessel when a lateral force is applied, wherein the blood vessel wall of a portion where the reinforcement member is placed has two layers including an inner wall and an outer wall , the reinforcement member is sandwiched between the inner wall and the outer wall , and the reinforcement member is not exposed to the outside, wherein the reinforcement member has an opening defined by an annular-shaped annular portion and wherein the opening corresponds to the branch portion and is disposed on the side surface at substantially the center in the length direction of the reinforcement member , characterized in that at the location of the annular potion , the inner wall and the outer wall are wrapped toward the outer surface and the inner surface, respectively, and wherein the branch portion has a branch portion blood vessel wall and wherein an end of the branch portion blood vessel wall is folded such that it forms a folded portion, wherein the folded portion is connected to the inner wall or outer wall of the blood vessel wall of the trunk portion around the annular portion . <EOS>