Let K be a totally real number field of degree r. Let K ∞ denote the cyclotomic Z 2 -extension of K and let L ∞ be a finite extension of K ∞ , abelian over K. The goal of this paper is to compare the characteristic ideal of the χ-quotient of the projective limit of the narrow class groups to the χ-quotient of the projective limit of the r-th exterior power of totally positive units modulo a subgroup of Rubin-Stark units, for some Q 2 -irreducible characters χ of Gal(L ∞ /K ∞ ).