  Possible consequences of ferromagnetic transition in dense matter suggested
recently by Kutschera and W{\'o}jcik, for the magnetic properties of neutron
stars, are studied. Specific model of dense matter, in which a small admixture
of protons is completely polarized due to their interaction with neutrons, is
considered. Magnetic field of neutron stars with a ferromagnetic core is
calculated within the framework of general relativity.
  Two types of boundary conditions at the ferromagnetic core edge are
considered, corresponding to normal and superconducting liquid envelope,
respectively. Numerical results for the neutron star magnetic dipole moment are
confronted with pulsar timing. To be consistent with observations,
ferromagnetic cores surrounded by a non-superconducting envelope, should
consist of weakly ordered ferromagnetic domains. If domains are highly ordered,
ferromagnetic core should be screened by a superconducting envelope.
