  We propose a lattice formulation of the chiral fermion which maximally
respects the gauge symmetry and simultaneously is free of the unwanted species
doublers. The formulation is based on the lattice fermion propagator and
composite operators, rather than on the lattice fermion action. The fermionic
determinant is defined as a functional integral of an expectation value of the
gauge current operator with respect to the background gauge field: The gauge
anomaly is characterized as the non-integrability. We perform some perturbative
test to confirm the gauge covariance and an absence of the doublers. The
formulation can be applied rather straightforwardly to numerical simulations in
the quenched approximation.
