A method of solving magnetoencephalographic and electroencephalographic inverse problems provides better grouping of moments of equivalent current dipoles than conventional methods. Locations of dipoles are fixed based on information using fMRI or the like. The magnitudes and orientations of the dipole moments are adjusted to fit magnetic fields and/or electrical potential distributions produced by the dipoles to magnetoencephalographically and/or electroencephalographically measured data. The method also includes grouping the dipoles in two stages, using the correlation coefficient of the magnitudes of the dipole moments as a criterion.