PURPOSE: To prevent the infiltration of splash of muddy water or the like and cool a disc rotor effectively.

CONSTITUTION: A dust cover 1 is provided with a circular dust cover body 1a and an edge part 1b projecting obliquely toward the outside of the outer peripheral surface 2b of a disc rotor 2. An air collecting part 3 is provided behind the upper side of the dust cover body 1a. An air collecting opening 3a is formed in the front opened state, and the upper face 3 is extended as far as above the outer peripheral surface 2b of the disc rotor 2 so as to engage the upper face 3 with the edge part 1b. Air flowing into the dust cover body 1a from the air collecting opening 3a blows through to the rear part of a vehicle along the outer peripheral surface 2b and inner sliding part 2c of the disc rotor 2 so as to flow outside from the air collecting part 3.