PURPOSE: To easily and safely stop an automobile at a narrow place, by generating a signal when a projecting contact member provided on the outside of the bumper of the automobile comes into touch with an obstacle.

CONSTITUTION: Normally, a steering wheel 13 is pulled out, a support shaft 9 is drawn forward with a wire 16 against a spring 11 and the contact member 10 made or rubber or the like is integrally fitted on the rear bumper 6. To park the automobile 1 at the narrow place, the steering wheel 13 is rotated to disengage a detent tooth 14 and a detent pawl 15 from each other, the contact member 10 is protruded backward from the body 5 of the automobile by the elastic force of the spring 11, a normally open contact 17a of a switch 17 is closed and a normally closed contact 18b of another switch 18 is opened. The automobile 1 is then moved slowly. If the contact member 10 comes into touch with an obstacle, the contact 18b is closed to sound a buzzer 21.