  The evolution of the multipolar structure of the magnetic field of isolated
neutron stars is studied assuming the currents to be confined to the crust.
Lower orders ($\le 25$) of multipole are seen to evolve in a manner similar to
the dipole suggesting little or no evolution of the expected pulse shape. We
also study the multifrequency polarization position angle traverse of PSR
B0329+54 and find a significant frequency dependence above 2.7 GHz. We
interpret this as an evidence of strong multipolar magnetic field present in
the radio emission region.
