PURPOSE: To prevent wiper operation when it is unnecessary by releasing the active state of a wiper driving part which is generated by the operation of a manual switch, when the next detection signal is not output within a prescribed time after the time point when a raindrop sensor stops outputting a detection signal.

CONSTITUTION: When a push switch 6a is pressed, the R-S flip-flop 7b of an automatic OFF-switch part 7 is set, and a wiper driving part 4 is set into active state. At the same time, a time limiting condenser C1 electric-discharges in a moment. When a detection signal is not output from a raindrop sensor 3, the condenser C1 is charged from a power source +B, and the positive input terminal voltage of a comparator 7a rises. If a detection signal is output from the sensor 3 before the above-described voltage reaches the threshold value of the negative input terminal of the comparator 7a, a wiper driving part 4 operates to operate a wiper. If the above-described detection signal is not output and the above-described voltage exceeds the above-described threshold value, the flip- flop 7b is reset, and the active state of the wiper driving part 4 is released.