To mount a wiper device tight on an end of a vehicle body while ensuring a wide wiping area of the wiper arms.

A pivot holder 2 is extended away from a pivot 8 into a generally trapezoidal mounting part 2a, while a vehicle body is provided with a trapezoidal insertion hole 13. For the installation of the wiper device, the mounting part 2a is first inserted in the insertion hole 13 with an inclined loose fit so that the pivot holder 2 is set in its installation position, and the pivot holder 2 is levered over a mount part 14 formed on the vehicle body so that the mounting part 2a is pressed on the upper or shorter side of the insertion hole 13.