A weld bead cutting device is configured such that, a liner made as liner portions are abutted on and welded to each other is rotated around a rotation axis extending in a direction along an abutting direction, and a weld bead is cut with a cutting tool arranged among rollers in a state where the rollers are pressed against an outer peripheral surface of the liner, the rollers being arranged on both sides of the weld bead on the liner in a direction along an extending direction of the rotation axis.