Abstract: A ring-shaped coupling comprising an inner ring, a rubber ring whose outer circumferential surface is divided by a circular groove into two conical surfaces each flaring toward the center in the axial directions and whose inner circumferential surface forming one solid surface is made to adhere by vulcanization to the outer circumferential surface of the inner ring, a pair of outer rings which are placed facing each other in the axial direction and a joining number. One of the inner circumferential surfaces of the outer rings having the shape of a conical surface flaring toward the other, and to the inner circumferential surfaces adhering by vulcanization the two conical sections of the outer circumferential surface of the rubber ring. The joining member puts the outer rings close to each other in the axial direction and fixes them in place in such a manner as to compress the rubber ring under the outer rings.