An artificial blood (10) has a trunk portion (12) with both ends connected to blood vessels, and access branch portions (14), (16) and a shunt branch portion (18) branched from the trunk portion. The access branch portions (14), (16) are disposed with a solid column-shaped access port (20) that plugs these branch portions. The access port (20) has a solid center portion (22) and a tube-shaped peripheral portion (24) disposed to surround the center portion (22). The peripheral portion (24) is harder than the center portion (22) and prevents the needle from deviating from the inside of the center portion (22). This enables a puncture to be easily made in a therapy in which a puncture is highly frequently made in a blood vessel.
