The twist-beam axle (10) comprises a central cross-member (11) compliant to torsion and a pair of trailing arms (12) fixed to side end portions (11a) of the cross-member (11) for articulated connection of the axle to the vehicle body and for support of the rear wheels. Each trailing arm (12) is formed by a pair of first, transversely inner half-shells (18, 19), that is, a front half-shell and a rear half-shell, respectively, securely connected to each other and to the respective end (11a) of the cross-member (11), and by a second transversely outer half-shell (20), securely connected to the pair of first half-shells (18, 19) so as to form therewith a structure having a closed cross-section.