To prevent a slip of a tire by connecting a nozzle for mud removal to an air compressor installed in an engine room or the like of a car with piping and installing a switch for operating the air compressor.

An air compressor 1 is provided in an engine room of a car. And a nozzle 2 is provided for jetting compressed air at a portion for mud removal of the car and the air compressor 1 and nozzle 2 are connected by piping 3. Also, a switch 8 for operating the air compressor 1 is provided. And when the road surface is slippery due to rain or snow, the switch is turned on, the air compressor 1 is operated, and compressed air is jetted from the nozzle 2 to the road surface. By doing this, the tire 4 tends to easily grip the road surface thereby preventing the slip.