To solve a problem in which backlash occurs in a valve lift variable valve gear when a valve lift variable operating shaft rotates through a gear device having a plurality of gears and the contact point of a fulcrum roller with a swing arm is shifted from a desired position when rotating the valve lift variable operating shaft.

This valve lift variable valve gear varying the valve lift of at least one valve of the intake valve and exhaust valve of the internal combustion engine is so configured that a cam provided to a camshaft is rotated by being brought into contact with the swing arm to thereby swing the swing arm around the contact point between the swing arm and a fulcrum portion having a projecting curved surface provided to the rotatable valve lift variable operating shaft and open/close a valve brought into contact with the end of the swing arm. The contact point between the swing arm and the fulcrum portion is set to a position where reaction generated in the contact point produces rotary torque only in one way in the valve lift variable operating shaft.