  We address a question whether the recently observed Higgs mass $M_{H} = 126$
GeV, of the order of the weak scale $M_{W}$, is calculable as a finite value in
the scnenario of gauge-Higgs unification. In the scenario formulated on a flat
5-dimensional space-time, the Higgs mass is calculable, being protected under
the quantum correction by gauge invariance, though the predicted Higgs mass is
generally too small compared with $M_{W}$. In the 6-dimensional SU(3) model,
however, a suitable orbifolding is known to lead to a mass of the order of
$M_{W}$: $M_{H} = 2M_{W}$ at the tree level, which has some similarity to the
corresponding prediction by the MSSM, $M_{H}$ leq (cos beta) $M_{Z}$. We
demonstrate first by a general argument and secondly by explicit calculations
that, even though the quantum correction to the quartic self-coupling of the
Higgs field is UV-divergent, its deviation from that of $g^{2}$ is calculable,
and therefore two observables, $M_{H}^{2}$ and Delta equiv
$(M_{H}/2M_{W})^{2}-1$, are both calculable in the gauge-Higgs unification
scenario. The implication of the precise value 126 GeV to the compactification
scale and the bulk mass of the matter field in our model is also discussed.
