PURPOSE: To improve an interlocking device for the door of a motor vehicle, simplify structure, and to achieve a necessary opening and closing function both during normal operation and abnormal operation.

CONSTITUTION: A central interlocking device for a motor vehicle has a function to open and close both when all performs normal operation and when an individual component is failed in operation. In the motor vehicle provided with this device, even when a door lock motor 60 is not functioned, opening is effected and locking is practicable. An external door grip and an internal door grip are locked selectively individually or simultaneously. Thereby, a control member 44 drive by a motor is provided with control discs 47 and 48 arranged in juxtaposition in parallel in cooperation with two unlocking levers 27 and 28. The control member is released by mechanically separating and revolving a door lock bar member 53 by a lock 54 to open a door 11. This interlocking device simplifies structure and provides an advantage that a lock motor 60 worked without load is used.