A manifestly gauge invariant and regularized renormalization group ow equat
ion is constructed for pure SU(N) gauge theory in the large-N limit. In thi
s way we make precise and concrete the notion of a non-perturbative gauge i
nvariant continuum wilsonian effective action. Manifestly gauge invariant c
alculations may be performed, without gauge fixing, and receive a natural i
nterpretation in terms of fluctuating Wilson loops. Regularization is achie
ved by covariant higher derivatives and by embedding in a spontaneously bro
ken SU(N\N) supergauge theory; the resulting heavy fermionic vectors are Pa
uli-Villars fields. We prove the finiteness of this method to one loop and
any number of external gauge fields. A duality is uncovered that changes th
e sign of the squared coupling constant. As a test of the basic formalism w
e compute the one loop beta function, for the first time without any gauge
fixing, and prove its universality with respect to cutoff function.