To detect a special behavior of an automobile and release a door lock automatically.

When an inclination angle detected by an inclination detection means 10 exceeds a predetermined inclination angle or it is judged that a ratio of the number of rotation of an engine to the number of rotation of wheels is out of a scope of a predetermined ratio based on signals from an engine number of rotation detection means 11 and a wheel speed detection means 12, a drive part 15 is operated and a door lock is automatically released based on the judgement signals.