Valve operating system in internal combustion engine

A valve operating system in an internal combustion engine having a cam shaft, said cam shaft having a valve operating cam and a stopping cam provided thereon, said valve operating system comprising:

• a common support member having an oil supply passage;
• a plurality of cam followers carried on said common support member, said plurality of cam followers arranged in a direction parallel to an axis of said cam shaft, and said plurality of cam followers operate in response to rotation of said cam shaft, a particular one of said plurality of cam followers is formed with a hydraulic pressure chamber and a communication passage which permits said oil supply passage to communicate with said hydraulic pressure chamber;
• a cylindrical roller shaft mounted on at least one of said cam followers other than said particular one cam follower;
• a connection switch-over means for switching over a state in which said cam followers are connected to one another and a state in which connection of said cam followers to one another is released, said connection switch-over means including a piston operated in response to a change in hydraulic pressure in said hydraulic pressure chamber, and said connection switch-over means mounted in said plurality of cam followers;
• and
• a roller rotatably carried on said cylindrical roller shaft in an arrangement coaxial with said piston in a connected state of said connection switch-over means, said roller being in rolling contact with the valve operating cam provided on said cam shaft,
• wherein said particular one of said plurality of cam followers is operated a smallest amount when said connection switch-over means is in a disconnected state.