  We offer an equivariant version of the classical monodromy zeta function of a
singularity as a series with coefficients from the Grothendieck ring of finite
G-sets tensored by the field of rational numbers. Main two ingredients of the
definition are equivariant Lefschetz numbers and the lambda-structure on the
Grothendieck ring of finite G-sets. We give an A'Campo type formula for the
equivariant zeta function.
