Generalized Covariant Derivative on Extra Dimension and Weinberg-Salam Model

The generalized covariant derivative on 5-dimen-sional space including 1-dimensional extra compact space is defined, and, by use of it, the Weinberg-Salam model is reconstructed. The spontaneous breakdown of symmetry takes place owing to the extra dimension under the settings that the Higgs field exists in the extra dimensional space depending on the argument $y$ of this extra space, whereas the gauge and fermion fields do not depend on $y$. Both Yang-Mills-Higgs and fermion Lagrangians in Weinberg-Salam model are correctly reproduced.