Aimed at improving adhesiveness between upper and lower interconnects in semiconductor devices, a semiconductor device of the present invention includes a second dielectric multi-layered film formed on a substrate, and containing a lower interconnect; a first dielectric multi-layered film formed on the second dielectric multi-layered film, and having a recess; an MOx film formed on the inner wall of the recess, and containing a metal M and oxygen as major components; an M film formed on the MOx film, and containing the M as a major component; and an electric conductor formed on the M film so as to fill the recess, and containing Cu as a major component, wherein the surficial portion of the interconnect fallen straight under the bottom of the recess has an oxygen concentration of 1% or smaller.