A variable valve lift device of an internal combustion engine having a first link arm rotatably supported at a fixed position of an engine body rotatably connected to a rocker arm, and a movable support shaft rotatably supporting one end portion of a second link arm of which an other end portion rotatably connected to the rocker arm is connected to a crank member formed in a crank shape having crank webs sandwiching the second link arm from opposite sides and a connecting part integrally joining both the crank webs at a position where interference with the second link arm is avoided. The crank member is rotationally driven with a drive device and an amount of lift of an engine valve is continuously changed, in addition to which, torsional rigidity of the crank member is ensured while ensuring assembly workability of the second link arm to the crank member, and reduction in size is made possible.