  We study the possibility that the Higgs and the inflaton are the same single
field or cousins arising from the extra space components of some
higher-dimensional gauge field. We take 5D supersymmetric gauge theory with a
matter compactified on S^1 as a toy model and evaluate the one-loop
contribution to the Higgs-inflaton potential. Our gauge-Higgs-inflaton
unification picture applied to the gauge field of intermediate energy scale
(\sim 10^{13} GeV) can explain the observed inflation parameters without
fine-tuning.
