A continuous variable valve duration apparatus includes a camshaft. A slider, which is mounted to the camshaft, has a camshaft sliding key and a cam portion of which a cam and a cam sliding key are formed thereto. The camshaft is inserted into the cam portion, and a relative phase between the cam and the camshaft is variable. A roller ring is connected with the camshaft sliding key and the cam sliding key. The roller ring is rotatably inserted into a roller ring guider, and the roller ring guider slidably inserted into a cylinder head. A control portion selectively changes a position of the roller ring guider to control a rotation center position of the roller ring.