DUST COVER FOR BALL JOINT

The purpose of the present invention is to provide a dust cover for a ball joint, the dust cover being configured so that the problem of the opening phenomenon of the small-diameter opening section of the dust cover is effectively eliminated even under low-temperature conditions in which the physical properties of an elastic material degrade. This dust cover consisting of an elastic material and used for a ball joint is configured so that a ball head formed at one end of the ball stud is held within a socket, a shaft at the other end of the ball stud is fastened and affixed to a knuckle, a large-diameter opening section at one end is affixed to and retained by the outer peripheral surface of the socket, and a small-diameter opening section at the other end is retained by the shaft. An annular stepped section is formed at the inner periphery-side end of the knuckle, the inner periphery-side end being in contact with the dust cover. A part of the small-diameter opening section is inserted in the space formed by the annular stepped section and the outer peripheral surface of the shaft, and the outer peripheral surface of the small-diameter opening section is restrained by the inner peripheral surface of the annular stepped section.