The invention relates to an anti-prizing separating structure used for a lock, which consists of a lock head, a driving gear, a driven gear and a part used for fixing the lock head. An elastic part is arranged between the lock head and the part used for fixing the lock head. When in normal use, a lock body is comparatively fixed in virtue of the elastic part; when a lock cylinder is twisted by an abnormal torque, the lock cylinder drives the lock body to turn and also drives the meshed driving and driven gears to be separated, so as to lead the torque brought to the clock cylinder for separating to fail. The invention has the advantages of simple structure, easy and simple manufacture, low cost. The lock heads installed on various bins, cases and automobiles, etc. objects all can adopt the structure of the invention, so the invention is provided with a wide application scope and a strong practicality.