It is made possible to optimize the effective work function of the metal for a junction and suppress the resistance as far as possible at the interface between a semiconductor or a dielectric material and a metal. A semiconductor device includes: a semiconductor film; a Ti oxide film formed on the semiconductor film, and including at least one element selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, Nb, Mo, Tc, Ru, Rh, Pd, Ta, W, Re, Os, Ir, and Pt; and a metal film formed on the Ti oxide film.