PURPOSE: To make mud clinging to the inside of a groove between twin tires scrapable automatically, by installing an arm rotatably at both sides of a car body via a fulcrum shaft, while situating a free end of the arm in the groove between these twin tires, in case of vehicles including a truck and the like provided with these twin tires.

CONSTITUTION: In case of vehicles including a truck and the like provided with twin tires, each fulcrum shaft 2 is projectingly installed at both sides of a car body 1, while a multistage folding arm 3 is rotstably supported on each of these fulcrum shafts 2 in position between twim tires 4. And, the arm 3 is moved downward, and a car is made to go forward in a state that the arm 3 is situated in a groove between these twin tires 4 whereby mud clinging to the inside of the groove between these twin tires 4 is scraped of by the said arm 3. With this constitution, the mud clinging to the groove inside between these twin tires 4 is thus scrapable.