  We consider a modification of the Wilson-Yukawa model to overcome its
difficulty that the fermion mass is not proportional to the Higgs vacuum
expectation value. In the modification scalar and fermionic regulator fields
are introduced so that all the physical fermion fields possess shift symmetry
when the Yukawa coupling vanishes. With the fermionic hopping parameter
expansion it is shown that the fermion mass is proportional to the Higgs vacuum
expectation value and that the coupling of fermion to the external gauge field
can be chiral if the hopping parameter of the scalar regulator field is taken
to the critical value.
