  We study the effect of dynamical gauge field on the Kaplan's chiral fermion
on a boundary in the strong gauge coupling limit in the extra dimension. To all
orders of the hopping parameter expansion, we prove exact parity invariance of
the fermion propagator on the boundary. This means that the chiral property of
the boundary fermion, which seems to survive even in the presence of the gauge
field from a perturbative point of view, is completely destroyed by the
dynamics of the gauge field.
