This ring rolling mill includes a main roll and a mandrel provided so as to be capable of being brought close to or separated from each other, and rolling a peripheral portion of a ring-shaped body in a radial direction of the ring-shaped body while the ring-shaped body is rotated along its peripheral direction in a state where the peripheral portion of the ring-shaped body is pinched in the radial direction between an outer peripheral surface of the main roll which is rotationally driven, and an outer peripheral surface of the mandrel which is rotatable. This ring rolling mill further includes a mandrel inclining/supporting mechanism which inclines and supports the mandrel with respect to the axis of rotation of the main roll such that the gap between the outer peripheral surface of the mandrel and the outer peripheral surface of the main roll differs on one side and on the other side as seen in a direction along the axis of rotation of the main roll.