A valve opening and closing apparatus includes a rocker arm which is in contact with a cam and causes a valve to be opened and closed using rotation of the cam. In particular, the valve opening and closing apparatus includes an eccentricity-creating unit which is disposed on the rocker arm and changes an eccentric position using rotation. A contact-maintaining unit of the valve opening and closing apparatus is disposed between the rocker arm and the eccentricity-creating unit so as to maintain the contact between the cam and the rocker arm when the cam is rotating.

A control method using a continuous variable valve duration apparatus may use a continuous variable valve duration apparatus including a wheel being mounted on a camshaft and having a wheel key to control duration of an intake valve of an engine, a cam device having a cam and a cam key, being adapted that the camshaft is inserted thereinto, and being disposed to can vary relative phase of the cam with respect to the camshaft, an inner bracket being connected with the wheel key and the cam key, a slider housing being adapted that the inner bracket is rotatably inserted thereinto and being disposed to can move vertically with respect to the engine, a controller varying a position of the slider housing to adjust rotation center of the inner bracket, and guide device guiding motion of the sliding housing.

A valve opening and closing apparatus is disclosed having one or a plurality of rocker arms in contact with the cam, such that each of the rocker arms causes a valve to be opened and closed using the rotation of a cam. An eccentricity-creating unit is disposed on the rocker arm, and changes an eccentric position using rotation of a rotary shaft extending through the plurality of rocker arms. A driving unit is connected to the rotary shaft of the eccentricity-creating unit to rotate the rotary shaft.