A high-pressure tank includes: a liner having a hollow liner body, a metal cap, a sealing member, and a reinforcing portion. The hollow liner body has an opening in an end portion in an axial direction, and a tubular insert ring harder than the liner body and integrated with the liner body to surround the opening. The metal cap is inserted into the opening. The sealing member seals between the insert ring and the metal cap. The reinforcing portion covers an outer side of the liner, and the insert ring extends to a front side in the axial direction with respect to the liner body and is mounted on the metal cap.