A sealing device including a first annular shield fixable to a first ring, a second annular shield facing the first and fixable to a second ring. A first shield annular sliding sealing lip cooperating with the second ring. At least first and second annular non-contacting sealing lips of the second shield. The first non-contacting lip includes a first portion extending in projection, and a second end extending axially and radially projecting from the first portion; being tapered towards a free end thereof, axially away from the first ring, which come into contact axially when the first annular lip is bent towards the first shield. The second non-contacting lip extends axially projecting from the first shield from the same side as the second portion of the first lip and beyond it and forms towards the first lip an annular collecting channel of possible contaminants which pass beyond the first annular lip.