A continuously variable valve lift device of an engine may include a cam shaft having an eccentric cam formed on an outer peripheral surface of the cam shaft so that an oscillating outer-race wheel is coupled to and oscillatable along the eccentric cam, an output cam being rotably fitted to the cam shaft, a sliding shaft for varying the position of the output cam by moving straightly in a front and rear direction according to an engine operating condition, in which the sliding shaft has a deviation adjustment member which is formed to be eccentric toward an outer peripheral surface thereof, and a rocker arm rotably fitted to the deviation adjustment member and one end of which is rotably connected to the oscillating outer-race wheel and the other end of which is rotably engaged with the output cam.