Abstract: Cap holder means which holds the inner peripheral surface of a cap has an outer diameter which may be shrunk to a value less than and expanded to another value greater than the diameter of the inner peripheral surface of the cap. When the cap holder means assumes a shrunk condition in which the outer diameter thereof is less than the diameter of the inner peripheral surface of the cap, the cap holder means is capable of smoothly receiving a cap from a cap feeder. Upon receiving a cap, the cap holder means may be changed to an expanded condition presenting an outer diameter greater than the diameter of the inner peripheral surface of the cap, thereby allowing caps of any varying internal diameter to be centered with respect to the cap holder means. This allows a smooth delivery of the cap from the cap holder means to a capping head.