PURPOSE: To cause the careful driving of an automobile and simplify the structure of a device for the careful driving, by turning off a steering switch provided on the peripheral part of the steering wheel, when the grasping force to the wheel has fallen, to give warning and stop the engine.

CONSTITUTION: A recess is provided on the peripheral part of a steering wheel 1. A steering switch 2 is fitted in the recess. Push springs 3 are applied to the switch 2 so that it can be turned on and off. An accessory circuit 18 is connected to the switch 2 through a relay 11. An engine circuit 19 and a warning circuit 18 are connected to a circuit 21 for the relay 11 through a snap switch 12. When the snap switch 2 is turned on, a relay contact 11' is connected to the engine circuit 19. When the snap switch is turned off, the relay contact 11' is connected to the warning circuit 20.