A control device (4) controls a varifocal lens (2) having a first substrate (20), a second substrate (22) facing the first substrate (20), and a varifocal component (14) disposed between the first substrate (20) and the second substrate (22). When an off signal is inputted to the varifocal component (14), the control device (4) stops applying voltage to the varifocal component (14), then applies voltage for a specific length of time, and finally stops the voltage. This reduces the duration of hazing that occurs during the switching of voltage application to the varifocal component (14).