  The Ginsparg-Wilson(G-W) relation is extended for supersymmetric free
theories on a lattice.
  Exact lattice supersymmetry(SUSY) can be defined without any ambiguities in
difference operators. The lattice action constructed by a block-spin
transformation is invariant under the symmetry. $U(1)_R$ symmetry on the
lattice is also realized as one of exact symmetries.
  For an application, the extended G-W relation is given for a two-dimensional
model with chiral-multiplets. It is argued that the relation may be generalized
for interacting cases.
