To provide a wiper device capable of preventing a motor for driving the wiper from rotating in the reverse direction even when an external force is applied when a wiper driving circuit is in an OPEN state.

In an oppositely sweeping type wiper device, wiper blades mounted on right and left wiper arms to be driven by separate motors overlap vertically at the lower inversion position. A one-way clutch 39 which transmits the rotation in the predetermined rotational direction of a motor 3a to the wiper blade side and prevents the motor 3a from being rotated in the reverse direction by the rotation in the direction opposite to the predetermined rotational direction to be input from the wiper blade side is provided on an output shaft 35 of the motor 3a and an armature shaft 33 or the like between the motor 3a and the wiper arm.