Abstract: A device to be mounted on a car for assisting a driver to make a parallel parking or a perpendicular parking, comprises displacement-sensing devices to measure specific distance that the car moves, obstacle-sensing devices for sensing the position of obstacles around a car, and a microcomputer that can, in accordance with the driver's instructions and the data received from aforesaid displacement-sensing devices and obstacle-sensing devices, generate various signals to tell the driver to drive the car forwards, to stop the car, to turn the car left or right, or to back the car so as to park the car along a specific path, further more, the microcomputer may generate an output signal to control the steering mechanism the transmission, the accelerator, and the brake system for backing the car into a parking space automatically.