A variable valve lift apparatus of an engine includes a first body rotated at within a preset angle range by rotating a high-speed cam coupled to a camshaft, a second body coupled to the first body or decoupled from the first body and rotated within a preset angle range by rotating a low-cam coupled to the camshaft when the second body is decoupled from the first body, a latching pin provided retractably forward of the first body such that the first body is coupled to or decoupled from the second body, and an actuating unit to retractably actuate the latching pin. The degree of the lift of the valve is variably controlled in two stages of high-speed and low-speed modes through the rotary motion of the high speed cam or low speed cam by coupling or decoupling the first and second bodies to or from each other.