  Grand gauge-Higgs unification of five dimensional $SU(6)$ gauge theory on an
orbifold $S^1/Z_2$ is discussed. The Standard model (SM) fermions are
introduced on one of the boundaries and some massive bulk fields are also
introduced so that they couple to the SM fermions through the mass terms on the
boundary. Integrating out the bulk fields generates the SM fermion masses with
exponentially small bulk mass dependences. The SM fermion masses except for top
quark are shown to be reproduced by mild tuning the bulk masses. One-loop Higgs
potential is calculated and it is shown that the electroweak symmetry breaking
occurs by introducing additional bulk fields. Higgs boson mass is also
computed.
