PURPOSE: To secure the safe visibility according to the rain quantity by installing a washer tank and a water tank, alternately spraying washer liquid and water when a rain water sensor senses rain, operate a wiper, and vary the operation speed of the wiper according to the rain quantity sensor.

CONSTITUTION: A washer tank 1 and a water tank 8 are installed. Further, a rain water sensor 9 and a rain quantity sensor 10 are installed, and the output signals of both the sensors 9 and 10 are inputted into a microcomputer. When the rain water sensor 9 senses rain fall through the microcomputer, pumps 2 and 2 are drivingly controlled, and a washing liquid and water are alternately sprayed on a windshield automatically, and wipers 5 and 6 are operated to wipe the windshield 7. Further, according to the rain quantity detected by the rain quantity sensor 10, each speed of the reciprocating movements of the wipers 5 and 6 is varied, and the visibility of the windshield 7 is kept properly.