  We investigate the gauge-Higgs unification models compactified on T^2/Z_N
that have the custodial symmetry. We select possible gauge groups, orbifolds
and representations of the matter fermions that are consistent with the
custodial symmetry, by means of the group theoretical analysis. The best
candidate we found is 6D SU(3)_C x U(4) gauge theory on T^2/Z_3 and the third
generation quarks are embedded into bulk fermions that are the symmetric
traceless rank-2 tensor of SO(6).
