The invention relates to a wall ring for an axial fan comprised of a supporting frame (1) on which a circular connecting piece (2) is formed, inside which the axial fan is arranged. The supporting frame (1) is assembled from a plurality of frame elements (6) by means of form and force-fitting connecting elements. The circular connecting piece (2) is formed of a plurality of circular segments (22) arranged circumferentially one after the other, said circular segments being connected to each other and to the supporting frame (1) by means of form and force-fitting or material-bonded connections or by such connection elements, respectively.