  In this paper the novel features of Yokoyama gaugeon formalism are stressed
out for the theory of perturbative quantum gravity in Einstein curved
spacetime. The quantum gauge transformations for the theory of perturbative
gravity are demonstrated in the framework of gaugeon formalism. These quantum
gauge transformations lead to renormalized gauge parameter. Further, we analyse
the BRST symmetric gaugeon formalism which embeds more acceptable Kugo-Ojima
subsidiary condition. Further, the BRST symmetry is made finite and
field-dependent. Remarkably, the Jacobian of path integral under finite and
field-dependent BRST symmetry amounts to the exact gaugeon action in the
effective theory of perturbative quantum gravity.
