PROBLEM TO BE SOLVED: To provide a sheet guiding cylinder having a sheet holding mechanism being quick in reaction and controllable by air pressure, in particular, and a simple structure for air control, regarding the sheet guiding cylinder which is used for a printing machine and has the sheet holding mechanism controllable by the air pressure. SOLUTION: The sheet guiding cylinder 4 has a constitution wherein at least one switching valve 23 provided fixedly for the cylinder 4 is provided with a first tank chamber 15 which is provided by one at least and which is connected to the valve through a connecting opening 25 and can give a negative pressure thereto. Moreover, the switching valve 23 is connected to the sheet holding mechanism 5 by a supply conduit and to an equipment control part by an electric conductor, while it is connected to an air pressure type mechanism by a conduit for compressed air.