An automotive rear safety checking apparatus which comprises a plurality of obstacle detectors mounted on the rear part of the automobile for radiating ultrasonic wave on the watching areas smaller in width than the width of the automobile respectively and detecting the ultrasonic wave reflected from an obstacle. The ultrasonic wave is radiated from the obstacle detectors in time division. Pulse signals in the number associated with the distance between the obstacle detector and the obstacle are generated in response to the detection of the ultrasonic wave reflected from the obstacle, so that the relative positions of the automobile and the obstacle, are indicated two-dimensionally in accordance with the pulse signal.