A clamp is provided, which includes a clamp main body including a plurality of concave members forming a cylindrical body by combining together, and a fixing device provided in any of the plurality of concave members for fixing the clamp to an attachment object; and an approximately arc-like buffer member disposed on an inner circumferential side of the concave member. On one side surface facing the concave member in the buffer member, a leg portion is formed to bulge out, and on another side surface opposite to the one side surface in the buffer member, an approximately concave-like holding surface is provided. Such clamp can hold long bodies with various diameters, and also can attenuate vibrations of the long bodies.