623A general expression for Hall conductivity including the effects of many-body interaction is derived on the basis of the Fermi liquid theory. It is exact as far as the most singular terms with respect to the quasiparticle damping are concerned. It is applicable for any types of interaction as far as the picture of Fermi liquid holds well. § 1. IntroductionThe systems in which electron-electron interactions cannot be neglected, such as heavy fermion systems!) and high-Tc oxide superconductors, are of current interest_ The former system exhibits the large T2-component of resistivity in its low temperature coherent regime. This behaviour is ascribed to electron-electron scattering with the Umklapp process_ Therefore, Hall coefficient should also be affected by manybody effects. Until now, many-body effects have been treated only within crude approximations. In metals, it seems dangerous to treat them on the basis of such approximate calculations as alloy analogy and Hubbard decoupling which neglect the momentum dependence of the self-energy. Moreover, we should include the vertex corrections originating from electron-electron interactions in order not to violate the Ward identity. These motivated us to seek an exact formula for Hall coefficient including the many-body effects on the basis of the Fermi liquid theory.Such a formula for conductivity was given by Eliashberg 2 ) in 1961. He collected all the terms which are, in the static limit, singular with respect to quasiparticle. damping, namely, divergent terms as the quasiparticle damping goes to zero. The result is given by (for simplicity, we give a static conductivity per spin) (J -e 2 f dp {_I (_ df) }v *v * , ,,11-(2n-)3 2yp de e=E(p) " 11 +f dp f dp' { 1·( df) .} *a 2