According to example embodiments, a lens positioning unit includes a fixed structure, a monolithic flexure hinge structure, any one of upper and lower portions of which is provided with a lens mount on which a lens is mounted and the other portion of which is secured to the fixed structure, and an input unit rotatably coupled to the fixed structure, the input unit serving to convert rotational motion into vertical translational motion so as to transmit the vertical translational motion to the upper or lower portion of the monolithic flexure hinge structure provided with the lens mount.