  In the gauge-Higgs unification scenario the Higgs field is unified with gauge
fields in higher dimensional gauge theory. The 4D Higgs field $H(x)$
corresponds to 4D fluctuations of the Aharonov-Bohm phase (Wilson line phase)
$\theta_H$ in the extra-dimension. An $SO(5)\times U(1)$ gauge-Higgs
unification model in the Randall-Sundrum warped spacetime with top and bottom
quarks is presented. Gauge couplings of the top quark multiplet induce
electroweak symmetry breaking by the Hosotani mechanism. The effective
potential $V_\eff (\theta_H)$ is found to be minimized at $\theta_H = \onehalf
\pi$ and the Higgs mass is predicted around 50 GeV. The $ZZH$ and $WWH$
couplings vanish at $\theta_H = \onehalf \pi$ so that the LEP2 bound for the
Higgs mass is evaded. The result is summarized in the effective interactions
for $\hat \theta_H(x) = \theta_H + H(x)/f_H$.
