The present invention entails a doorknob security device for preventing access to the outer surface of the doorknob and particularly to a keyhole or other locking and unlocking mechanisms formed about the surface of the knob. In particular, the security device of the present invention comprises an outer main housing and a rotatable inner closure panel. The inner closure panel is rotatable from a closed to an open position. In the open position the security device easily accepts a doorknob. In the closed position the security device encompasses and closes the doorknob preventing access to the same.