PURPOSE: To improve rolling characteristics, pressure characteristics and a printing quality by preforming a cover in the form of a foam by adding a foaming agent and an inhibitor, and forming of a multi-component material to be a volumetric compressibility between the cylinder and the cover.

CONSTITUTION: An offset cylinder 1 has a replaceable support cylinder 2, which has a volumetric compressible cover 3. As a starting material of the cover 3 for forming a base layer, a material containing a polyol as a main body such as, for example, a material containing a polyurethane or a silicone as a main body is used. And, a foaming agent and an inhibitor are added to restrict desired size and number of fine foams. And, a volumetric compressive layer is freely foamed and covered. Thus, a rotary press having a plastic seamless sheath having fine foams without connecting to each other or particularly the cylinder 2 of the offset printing machine is obtained.