Abstract: The subject invention is a door lock security device adapted to provide a means for preventing a doorknob lock from being opened by a master key or other means through the keyhole while the room is locked from the outside, such device comprising a cover member to envelope and otherwise cover a doorknob of the type which has a locking mechanism integrated therein. The subject covering device comprises a circular ring member comprising two separate retractable members, which are pivotably mounted to one another at a common point about which they can retract or close relative to one another. The circular ring member is adapted to encircle the doorknob in a peripheral manner and is provided with a solid frontal portion to cover the key insert. The solid frontal portion is adapted to fit securely against the outer extremity of the doorknob in which the key slot is structured so as to prevent one from inserting a key or other object into the key slot while it is so covered.