Abstract: A wiper apparatus is provided with a switching mechanism for spraying washing fluid in the leading direction of movement of a wiper blade at all times by actuating a valve synchronously with the oscillating movement of the wiper blade. The switching mechanism is composed mainly of a base member secured to the vehicle body and a casing member secured to the wiper arm which are disposed coaxially with a pivot shaft and coupled rotatably with each other to form a valve chest therebetween. A pair of valves attached to a disc member having an arcuate slot is disposed in the valve chest so as to alternately block ducts communicating with washer nozzles disposed on opposite sides of the wiper arm according to the engagement of opposite ends of the arcuate slot of the disc member with a contact piece on the base member every time the wiper blade arrives at the lower and the upper turning positions.