  We study in details on how gauge bosons can acquire mass when the chiral
symmetry dynamically breaks down for massless gauge theory without scalars.
Introducing dynamical scalar fields into the original gauge theory, we show
that when the chiral symmetry breaks down, the theory gives gauge boson masses
different from what would be obatained if an elemetary Higgs is included. We
clarify the reason and propose one method how to calculate gauge boson masses
in the case of dynamical gauge symmtry breakdown. We explain the method by
using an example in which SU(5) massless gauge theory breaks down to SU(4) with
massless fermions in appropriate representations.
