To favorably prevent a door lock knob from being moved to a release position in error and prevent the door lock knob from being moved to a release position by a passkey, a wire or the like.

This lock means includes a mounting body 1 fitted to the inside surface of a door having a door lock knob A, a binding body 2 supported on the body to bind the movement of the door lock knob A to the release position and also serves as a cover 3 for covering the door lock knob A, and an operating body 5 for inhibiting/releasing the movement. While getting in a car, the cover 3 covers the door lock knob A, thereby preventing the door lock knob A from being moved to the release position, and when going out to the outside of the car, the binding body 2 is fixed by the operation of the operating body 5 to bind the movement of the door lock knob A and prevent burglar.