PURPOSE: To reduce the cost, save the space, save the power, and simplify the maintenance by mounting one oscillator for common use when multiple microwave-applied detection devices are installed on a car.

CONSTITUTION: A microwave oscillator 9 is operated by a power supply 11 and generates microwave signals, which are distributed by a distributor 12 and fed to front and rear obstacle detection radars 1, 2, side rear obstacle detection radars 3, 4, a ground speed detection radar 5, a raindrop detection radar 6, and an engine top end point detector 8 respectively through a transmission means 100 for stable operations. Information signals from individual devices are concentrated to a central control unit 10, and after a calculation process, their data are displayed on a display unit 13 in a digital form. The display unit 13 is allowed to generate an alarm based on the obstacle detection information as required.