Abstract: The invention relates to a rotary locking mechanism which is preferably intended for lock cylinders. The inventive mechanism includes an electric motor, a locking bolt, an inertial rotating mechanism which converts the rotation of the motor into a rectilinear movement along the axis of the locking bolt, an elastic energy accumulator which is arranged in opposition to the backward retraction travel of the locking bolt and a rectilinear guide mechanism for the working extension/retraction travel of the locking bolt.