A lever structure for securing one or more pressers and/or for closing the flaps of a ski boot, includes a device for the fine adjustment of the working length of one or more traction elements. The device includes at least one knob which can be accessed by the skier and is associated with a lever arm in an oscillating manner and without fixed connections. The knob has an internally threaded cavity which acts as seat for a complementarily threaded pawl which is rigidly associated with a traction element. The device is considerably simple in execution and has modest costs in view of the absence of pivots, rivets and other means for interconnection between the lever and the knob.