We propose to perform neutron diffraction experiments on a powder sample of a multiferroic hexaferrite PbFe12O19. A recent paper has reported room temperature multiferroic behavior in PbFe12O19. However, the mechanism of ferroelectric polarization are not clear, because the space group reported previously is centrosymmetric P63/mmc despite the fact that it exhibits ferroelectric polarization. In order to investigate structural distortion and magnetic orderings associated with the ferroelectric polarization, we would like to perform neutron diffraction experiments on WISH.