The crystal structure of the As-containing mineral holtite II was refined by the Rietveld method. The orthorhombic unit-cell parameters are a = 4.6893(1) Å, b = 11.881(1) Å, c = 20.394(1) Å, sp. gr. Pnma, Z = 4. Holtite II has an octahedral framework structure composed of two types of nonequivalent columns of Al octahedra, which was found in the structures of dumortierite-group minerals and holtite I. The differences in the structures of holtite II and holtite I were revealed. These differences are associated with the differences in the composition and configuration of the columns of Al(1) polyhedra, which are located inside the framework and are linked to SiO₄ tetrahedra, as well as with the arrangement of pyramidal SbO₃ groups.