  A coherent state of pions is introduced to the nonrelativistic quark model.
The coherent pair approximation is employed for the pion field in order to
maintain the spin-isospin symmetry. In this approximation the pion is localized
in the momentum space, and the vertex form factor in the pion-quark interaction
is derived from this localization. The nucleon masses and wave functions are
calculated using this model, and our results are compared to those of the quark
model with the one pion exchange potential. Similar result is obtained for the
mass spectrum, but there exists a clear difference in the internal structure of
nucleon resonances.
